Synthetic cvd diamond

FIELD: chemistry.

SUBSTANCE: invention relates to technology of production of synthetic diamond material, which can be applied in electronic devices. Diamond material contains single substituting nitrogen ( N s 0 ) in concentration more than 0.5 ppm and having such complete integral absorption in visible area from 350 nm to 750 nm, that at least nearly 35% of absorption is attributed to N s 0 . Diamond material is obtained by chemical deposition from vapour or gas phase (CVD) on substrate in synthesis medium, which contains nitrogen in atomic concentration from nearly 0.4 ppm to nearly 50 ppm, and gas-source contains: atomic part of hydrogen, Hf from nearly 0.40 to nearly 0.75, atom part of carbon, Cf, from nearly 0.15 to nearly 0.30; atomic part of oxygen, Of, from nearly -.13 to nearly 0.40; and Hf+Cf+Of=1; ratio of atomic part of carbon to atomic part of oxygen, Cf:Of, satisfy the ratio nearly 0.45:1<Cf:Of< nearly 1.25:1; and gas-source contains atoms of hydrogen, added in form of hydrogen molecules, H2, with atomic part of the total quantity of present atoms of hydrogen, oxygen and carbon between 0.05 and 0.40; and atomic parts of Hf, Cf and Of represent parts from the total quantity of atoms of hydrogen, oxygen and carbon, present in gas-source.

EFFECT: invention makes it possible to obtain diamond material with rather high content of nitrogen, which is evenly distributed, and which is free of other defects, which provides its electronic properties.

17 cl, 11 dwg, 6 ex

 

The invention relates to a method for synthesizing synthetic CVD diamond material and high quality synthetic CVD diamond material.

Diamond has high hardness, good abrasion resistance, low compressibility and low coefficient of thermal expansion. Diamond may also have a very high coefficient of thermal conductivity, and it can be very good electrical insulator. This makes the diamond a desirable material for many applications. For example, through the use of its thermal conductivity diamond can be a great heat sink material for electronic devices.

In certain electronic devices the ability to legitamate diamond is nitrogen important in order to break the Fermi level.

Synthetic diamond material synthesized using the methods of synthesis at high pressure - high temperature (WDT), usually contains significant concentrations of nitrogen, in particular single substitutional nitrogen (Ns0), making it yellow. To avoid this, you should take special precautions to exclude nitrogen from the synthesis medium. In addition, the diamond material produced using methods VDT-synthesis, shows a much different absorption of nitrogen impurities on surfaces with different crystallographic ori what ntaria (which are surfaces, corresponding to different growth sectors), which are formed during the synthesis. Therefore, the diamond material has a tendency to show areas of different colors coming from different concentrations of the impurity nitrogen in different growth sectors. In addition, it is difficult to control the process VDT-synthesis sufficiently in order to obtain uniform and the desired concentration of nitrogen across even a single growth sector within the synthesized diamond material. Moreover, in VDT-synthesis is usually seen impurities resulting from the process of synthesis and used catalysts - examples are the inclusion containing cobalt or Nickel, the signs, which can cause localized and non-uniform voltage, which deteriorates the mechanical, optical and thermal properties.

Using a CVD method such as the method described in US 7172655), it is possible to synthesize diamond material that contains significant concentrations (up to approximately 10 hours per million [ppm]) Ns0but this diamond is usually brown in color. It is believed that this brown color is caused by the presence of the introduced material other defects than the Ns0though caused by the addition of nitrogen in the environment CVD synthesis.

Diamond material with its own conductivity is an indirect banned list is th area of about 5.5 eV, which is transparent in the visible part of the spectrum. The introduction of defects, also called "color centers"that have associated energy levels within the forbidden zone, gives the diamond a characteristic color, which depends on the type and concentration of color centers. This color may occur as a result of absorption or photoluminescence, or their combinations, but usually the absorption is the predominant factor. For example, it is well known that the defect Ns0causes the absorption on the blue edge of the visible spectrum, that is, in itself, causes the material to have a yellow color. Similarly, it is known from the work of Walker (J. Walker, "Optical Absorption and Luminescence in Diamond", Rep. Prog. Phys., 42 (1979). 1605-1659)that, when this yellow material is irradiated with high-energy electrons to create vacancies (crystal lattice, of which removed the carbon atoms), and annealed to induce migration and the final capture of vacancies, impurity atoms of nitrogen, the formation of NV centers.

EP 0671482, US 5672395 and US 5451430 describe ways to reduce the undesirable defect centers in CVD diamond using VDT-processing, and US 7172655 implements a method of annealing to reduce korichnevato single-crystal stone. The most complete removal of brown color is achieved at annealing temperatures above about 1600°C and usually requires stabilizing the diamond pressures. However, this treatment is expensive and complex the m process in which the outputs of the fit can seriously depend on the cracking stones, etc. in Addition, due to the diffusion of defects such strategy annealing is not necessarily compatible with the prevention of aggregation of nitrogen or with the manufacture of high-performance electronic devices, where it may be important to control the location of the defects. It is therefore considered desirable to be able to directly synthesize diamond material that is not brown, but retains the desired high concentration of Ns0using CVD methods.

There are many variations of the CVD method, the deposition of diamond, which are now generally accepted and widely described in the patent and other literature. This method typically includes providing a gas source, which, when dissociation with the formation of the plasma, can provide reactive gas particles such as radicals and other reactive particles. The dissociation of the gas source is called a source of energy, such as microwave, RF energy, flame, hot thread or ink-jet method, and produces reactive gas particles, which provide the ability to Deposit on the substrate and to form a diamond. Most modern level of technology focuses on the use of hydrogen (based on H) plasma, usually containing H2with small additions of m is Tana, usually in the range from 1 to 10 vol.% (see, for example, J. Achard et al., "High quality MPACVD diamond single crystal growth: high microwave power density regime", J. Phys. D: Appl. Phys., 40 (2007) 6175-6188), and oxygen or oxygen-containing particles is usually at the level of from 0 to 3% vol. (for example, Chia-Fu Chen and Tsao-Ming Hong, Surf. Coat. Technol., 54/55 (1992), 368-373). Next, oxygen and oxygen-containing particles will be jointly called "O-containing particles, and they are formed from O-containing source gas source.

Known intentional additives nitrogen in the environment synthesis (for example, Samplenski et al., Diamond and Related Materials, 5 (1996), 947-951), usually with the aim of increasing the growth rate or improve the quality of the diamond some other ways, for example by reducing stress and cracking (WO2004/046427). In these ways, while the addition of nitrogen in the environment synthesis actually takes some level of nitrogen in the solid body, it is not the main goal, and the whole process is, in General, aim at minimizing the introduction of nitrogen and other related defects in the synthesized diamond material. One exception is that when the goal is the creation of color centers in diamond material in the form of nitrogen defects (for example, WO2004/046427), such diamond material is rarely used in the applications considered here due to the high concentration of other defects than the single substitutional nitrogen, embedded in the diamond material.

Although most modern level of technology focuses on the plasmas on the basis of N, containing little or no containing O-containing particles, there are also references to the importance of O-containing particles in the etching of non-diamond carbon, particularly in the context of the synthesis of polycrystalline diamond CVD methods (see, e.g., Chen et al., Phys. Rev. B, vol. 62 (2000), pages 7581-7586; Yoon-Kee Kim et al., J. Mate. Sci.: Materials in Electronics, vol. 6 (1995), pages 28-33), and in the process of synthesizing "high color" of the diamond, which is free from impurities that appear when using plasmas based on N experiments with synthesis processes under similar pressures and energies. Critical that in this field the prior art nitrogen, embedded in the diamond material, is considered one of the defects, minimize, and these methods prescribe to reduce the content of nitrogen together with other types of defects (for example, WO 2006/127611).

Based on the foregoing, there remains a need in the CVD method of obtaining single-crystal diamond, which allows you to control the content of defects, and its product is a synthetic CVD al is Azay. There is also a need for high-quality color (i.e. high quality) synthetic CVD diamond material itself (per se).

In particular, there is a need in CVD diamond material produced by direct synthesis, with a relatively high nitrogen content, which is evenly distributed, and which is free from other defects, such as inclusions, usually associated with processes VDT-synthesis. Moreover, there is a need for such CVD diamond material having a color which is not dominated by brown defects that do not contain nitrogen, but instead dominated by yellow tint due to the presence of single substitutional nitrogen. There is also a need in CVD diamond material in which the electronic properties are mainly provided with single substitutional nitrogen, but not particularly limited other defects, usually arising from nitrogen in the growth process.

The present invention provides a method of chemical deposition from the vapor or gas phase (CVD) synthetic diamond material on a substrate in an environment of synthesis, containing:

providing the substrate;

providing a gas source;

the dissociation of the gas source; and

providing opportunities homoepitaxial synthesis of diamond on the substrate;

in this environment synthesis contains nitrogen in atomic conc is Tracii from about 0.4 h/m to about 200 hours/million;

and when the gas source contains:

a) the atomic ratio of hydrogen (Hffrom about 0.40 to about 0.75;

b) the atomic percentage of carbon, Cffrom about 0.15 to about 0,30;

(C) atomic ratio of oxygen Offrom about 0.13 to about 0,40;

when Hf+Cf+Of=1;

the ratio of the atomic fraction of carbon atomic fraction of oxygen, Cf:Ofcorresponds to a value approximately equal to 0.45:1<Cf:Of< approximately 1.25:1; and the gas source contains hydrogen atoms are added in the form of hydrogen molecules H2when the atomic fraction of the total numbers of atoms of hydrogen, oxygen, and carbon between about 0.05 and about 0,40; and

when this atomic fraction of HfCfand Ofrepresent the proportion of the total number of atoms of hydrogen, oxygen and carbon present in the gas source.

The gas source contains hydrogen, carbon and oxygen in the atomic proportions calculated on the total number of atoms of hydrogen, oxygen and carbon present in the gas source, HfOfand Cf. Hydrogen can be achieved by using H2or other sources, such as CH4and other

The inventors unexpectedly found that by adding hydrogen in the form of molecules N2to a gas source containing O-containing sources (e.g., gas-source CH4/CO ), you can modify the growth conditions of the diamond so as to obtain the synthetic CVD diamond material and with a high concentration of nitrogen in the form of Ns0and with the low concentration of other defects.

CVD methods best as methods of synthesis of single-crystal diamond, as they provide a more uniform, adjustable method of production of synthetic diamond material. On the contrary, WDT methods give material with poorly controlled levels of Ns0and, therefore, a large variation of the concentration of Ns0between growth sectors and material with other impurities and inclusions.

Without wanting to be bound by theory, it is believed that the applicable ranges of the parameters of the synthesis temperature, pressure and energy density for the synthesis of CVD diamond material can be decreased by the addition of O-containing sources in the gas source. Plasma containing O-containing particles may be less stable and more prone to the formation of, for example, monopolar arcs than plasma on the basis of N, and the density of the microwave energy and pressure processes using O-containing particles in the plasma, can be forced to be lower than for processes with plasma based on N. One advantage of adding a certain amount of hydrogen, preferably in the form of H2in the process, containing About the content of Asia particles, is that it allows the use of higher density microwave energy and pressure. Thus, working pressure, and density of the microwave energy can be increased before the synthesis process is violated because of a tendency to the formation of monopolar arcs.

Here the expression "plasma on the basis of H" is defined as a plasma containing atoms of hydrogen, oxygen and carbon, in which the atomic fraction of hydrogen atoms (Hf), expressed as a proportion of the total number of atoms of hydrogen, oxygen and carbon in the gas source, which forms the plasma, is about to 0.80 or more, alternatively about 0.85 or more, alternatively about 0.90 or more. For example, the composition of the gas source from 600 SMS3H2, 30 SMS3CH4(where "SMS3" stands for "standard cubic centimeters", and they represent flows into the chamber containing the plasma) has an atomic ratio of hydrogen

((600×2)+(30×4))/((600×2)+(30×5))=0,98,

and this plasma is a plasma-based N.

Here the expression "plasma based On" is defined as a plasma containing atoms of hydrogen, oxygen and carbon, in which the atomic fraction of oxygen atoms (Of), expressed as a proportion of the total number of atoms of hydrogen, oxygen and carbon in the gas source, which forms the plasma, is about 0.10 or more, alternative is about 0.15 or more, alternative approximately of 0.20 or more, and the atomic fraction of hydrogen atoms (Hfin gas-source, which forms the plasma, is about 0.75 or less, alternatively about 0,70 or less, alternatively about of 0.60 or less, alternatively about 0.50 or less. For example, the composition of the gas source of the 290 SMS3CO2, 250 SMS3CH4and 230 SMS3H2has an atomic ratio of oxygen (Of)

(290×2)/((290×2)+(25×5)+(230×2))=0,22

and the atomic ratio of hydrogen (Hf)

((250×4)+(230×2))/((290×2)+(25×5)+(230×2))=0,56,

and this plasma is a plasma-based O.

One reason why so many of the modern technology associated with plasmas on the basis of N (for example, a plasma formed from a mixture of gases-sources, which mainly represents H2), is considered as consisting in the fact that plasma containing a large proportion of O-containing particles (e.g., plasma, formed due to the dissociation of gaseous sources on the basis of CO2/CH4), is harder to control at high pressures and high densities of microwave energy. In some circumstances, the "quality" of the diamond synthesized at specific pressure and energy density, it may be better (i.e. the content of defects may be lower) for a plasma with a large proportion of O-containing particles than for plasma based on N, when the analogue is offered by the combination of pressure and energy density, and models usually assume that this is based on the excellent ability of O-containing particles to the etching. However, the plasma on the basis of N can be operated at much higher pressures and energies, which means that, although O-containing particles can poison Almazny carbon more effectively "atom"on the diamond surface are much smaller flows etching particles than for plasma-based N with higher energy and pressure. These smaller streams etching particles typically cause the contents of the defects in the product to be higher for the material synthesized in the optimized plasma containing O-containing particles, compared with process-optimized plasma-based N.

In addition, it has been previously shown that the addition of only hydrogen to the gas sources on the basis of CO2/CH4reduces the quality of the synthesized diamond material (Chia-Fu Chen and Tsao-Ming Hong, "The role of hydrogen in diamond synthesis from carbon dioxide-hydrocarbon gases by microwave plasma chemical vapor deposition", Surface and Coating Technology, vol 54/55 (1992), pages 368-373).

On the contrary, the inventors unexpectedly found that by adding N-containing sources (in particular by adding hydrogen atoms in the form of H2) to a gas source in a carefully controlled amount of pressure which can stably flow process CVD synthesis, can be reduced (e it is believed that the presence of hydrogen increases the stability of the plasma). This can provide an increase in pressure and density microwave energy synthesis, and thus, when combined with significant levels of oxygen with the regime of energy and pressure, which can be a valid due to the presence of appropriate levels of hydrogen were found conditions that may allow significant levels of single substitutional nitrogen to enter into the lattice of the diamond, while minimizing other defects normally associated with the nitrogen present in the environment of synthesis. It can give high quality synthetic CVD diamond material.

Without wanting to be bound by theory, the inventors believe that when the conditions proposed in the present invention, the increased density of microwave energy makes possible a more rapid etching of non-diamond carbon than is usually possible in plasmas containing O-containing particles. This is a fast etching may occur because of the wonderful ability of O-containing particles to the etching, which may become more pronounced with higher pressure process. It is not clear and was definitely unpredictable that it will have high selectivity in etching found in practice, providing a very effective etching the non-diamond carbon is a and those defects, which are causing brown color, but making possible an unusually high level of introduction of nitrogen in the CVD diamond material. Thus, clearly, the material obtained by the method according to the present invention, shows a significant absorption associated with single substitutional nitrogen, but very low absorption associated with coricnevatogo resulting from other defects than the single substitutional nitrogen, which are considered to be caused by the addition of nitrogen in the environment CVD synthesis.

The present invention additionally provides a synthetic CVD diamond material obtained by the method according to the present invention.

The present invention additionally provides a synthetic CVD diamond material containing single substitutional nitrogen (Ns0) concentration of greater than about 0.5 hours/million and with such a complete integrated absorption in the visible region from 350 nm to 750 nm, at least about 35% of the absorption is attributed to the Ns0.

Preferably, the CVD diamond material according to the invention is a single crystal CVD diamond material.

The present invention additionally provides a gemstone containing synthetic CVD diamond material of the present invention. The present invention additionally provides the AET application of synthetic CVD diamond material of the present invention as a precious stone. These precious stones are the best, because the defects present in the synthetic CVD diamond material of the present invention provide a yellow color, which is similar to the yellow painted yellow natural diamond (for example, the so-called diamond Cape Yellow"), making the gems more attractive for those who have a preference for natural-looking colors.

The present invention additionally provides for an electronic device containing synthetic CVD diamond material of the present invention.

The present invention additionally provides for the use of synthetic CVD diamond material of the present invention in an electronic device. These electronic devices are advantageous because high and uniform concentration of Ns0the substrate on which the device is manufactured, effectively attaches the Fermi level, providing a substrate, which can be precipitated subsequent Apollo has its own conductivity or doped diamond with a low density of extended defects.

Here, to describe the diamond material of the color grade (class), refer to the scale of gradations of colors, which is the scale of the Gemological Institute of America ("GIA"), where "high-quality silver is t" - this class "L" or higher (i.e., classes D, E, F, G, H, I, J, K or L), GIA grade of "D" is the color of the highest quality, which is closest to the completely colorless. The color value in the color field classification of diamond is well understood, and the diamonds are sorted using the same methods on the same scale in laboratories classification of gemstones around the world. The relationship between the perceived color and grade or class is given in V. Pagel-Theisen, "Diamond Grading ABC The Manual", 9thEdition (2001), Rubin & Son, Antwerp, Belgium, page 61 (folding table).

Quantitative measurement of color in a diamond is well established and is described using the chromaticity coordinates CIE L*a*b", and their application is described in WO 2004/022821. Coordinates a* and b* lay along the axes x and y of the graph, and the hue angle measured from the positive axis and* to the positive b axis*. Thus, the hue angle more than 90° and less than 180° lies in the upper left quadrant of the graph and*b*. In this scheme to describe color L* represents brightness, and the fourth coordinate With* represents saturation.

In the context of this invention, the term "quality" is used as meaning "suitability for purpose", and therefore one material when used for specific applications, is considered to be "higher quality"than other material, if it provides a better or improved technical the solution of the problem to be solved.

In the art commonly called "synthesis" diamond material "growing" of the diamond material. Terms such as "rate of growth" and "growth sector" should therefore be understood from this point of view.

Wednesday synthesis contains a gas source, which itself contains carbon atoms, hydrogen atoms and oxygen atoms in the form of molecules, atoms, radicals or ions. There may be other particles, deliberately added to the environment synthesis (in particular, by adding these particles in gas-source) in larger or smaller quantities, such as inert gases (e.g. helium, neon, argon, krypton, etc.) or nitrogen. In addition, in a mixture of gases-sources can be impurities.

The proportion of atoms in the environment of synthesis, which are S, N and O, may be about 70% or more, alternatively about 80% or more, alternatively about 85% or more, alternatively about 90% or more, alternatively about 95% or more, alternatively about 98% or more.

Wednesday synthesis may optionally contain one or more inert gases selected from helium, neon, argon, krypton and xenon. These inert gases may be added in Wednesday synthesis gas source, i.e. they are present in the gas source. Inert gases may be present in the gas source to the atomic fractions, Xfbetween about 0 and about 0.5, alternative megaprimer 0 and about 0.3, alternate between approximately 0 and approximately 0.2, alternatively between about 0 and about 0.1, alternate between approximately 0 and approximately 0.05; where Xf+Hf'+Cf'+Of'=1. Atomic fraction of Hf', Cf' and Of' represent the proportion of the total number of atoms of hydrogen, oxygen, carbon and inert gas present in the gas source. It is clear that when Xf=0; Hf=Hf', Cf=Cf' and Of=Of'. Since the inert gases are inert from a chemical point of view, they do not play a role in what is happening in the plasma chemical processes and can be ignored in this respect. However, the presence of inert gases can affect the physical characteristics of the plasma, such as its conductivity, or can act as a third body that can facilitate chemical reactions between other particles, not actually participate chemically in the reaction. Therefore, the inventors believe, without regard to any particular theory, that the presence of inert gases, in particular Ar, in small quantities, although it is not necessary for the present invention may have preferential effects.

Wednesday synthesis contains the gas source and the gas source contains hydrogen atoms added as a hydrogen molecule, H2with atomic fractions, expressed as a proportion of the total number available is the corresponding hydrogen atoms, carbon and oxygen, from about 0.05 to about 0.40 to, alternatively from about 0.10 to about 0.35 in, alternatively from about 0.15 to about 0,30, alternatively from about 0.05 to about 0.10 to alternative from approximately 0.10 to approximately 0.15, alternatively from about 0.15 to about 0,20, alternatively from about 0.20 to about 0.25 in, alternatively from about 0.25 to about 0,30, alternatively from about 0.30 to about 0.35 in, alternatively from about 0.35 to about 0.40 in. The remaining hydrogen atoms (i.e. those derived from the added molecules of H2) come from other sources, such as CH4and other

The hydrogen gas source is in the form of hydrogen (H2or hydrogenous sources (hereinafter collectively referred to as N-containing sources, such as H2CH4and other hydrocarbon particles, including hydrocarbons, which also contain oxygen, such as aldehydes, ketones and others

The carbon in the gas source is in the form of carbon-containing sources, such as CO (carbon monoxide), CO2(carbon dioxide), CH4other hydrocarbons (alkanes, such as ethane, propane, butane, and others; alkenes, such as Eten, propene and others; alkynes such as ethyn, identical propyne and others), oxygen-containing hydrocarbons such as alcohols, aldehydes, esters, carboxylic acids, etc.

Color the d in the gas source is in the form of oxygen or oxygen-containing sources (hereinafter together called O-containing sources), for example About2About3(ozone), CO, CO2, oxygen-containing hydrocarbons such as alcohols, aldehydes, esters, ethers, carboxylic acids, etc.

As the mixture of gases-sources essentially breaks down into its constituent atoms during the synthesis process, and these components will be transformed into a mixture of particles, which is a thermodynamically equilibrium composition for a specific mixture of atoms or close to it, the choice of molecular particles, which comprise a mixture of gases-sources, is dictated by the requirement to achieve a specific composition of the plasma and the ability to ignite and maintain the plasma in the selected mixture of molecules. The choice of gases forming a mixture of gases-sources, to some extent also driven by cost, availability, cleanliness and ease of handling; for example, CH4, CO, CO2N2and O2all easily available as a stable, bulk gases in a range of different chemical purity and, hence, may be preferred.

When the dissociation of the gas source, these sources form a plasma, respectively, hydrogen or hydrogen-containing particles (along N-containing particles), carbon-containing particles and the oxygen or oxygen-containing particles (together About-containing particles). Usually dissociatively gas source will contain radicals in which Orada (N), the radicals of carbon monoxide (COand dvuuglerodnye particles radicals (for example, C2Hxwhere x is less than 6). The presence of these particles can be determined by methods such as optical emission spectroscopy ("ECO").

The gas source can be formed from molecular particles, such as CO, CO2CH4and H2so that the atomic fraction of carbon, Cf, hydrogen, Hf, and oxygen, Ofin gas-source lie in the following intervals:

of 0.15<Cf<0,30, alternative 0,18<Cf<0,28 alternative 0,20<Cf<0,25;

0,40<Hf<0,75 alternative 0,42<Hf<0,72 alternative of 0.45<Hf<0,70; and

0,13<Of<0,40 alternative of 0.15<Of<0,38 alternative 0,18<Of<0,35.

You can represent the position of any gas source containing the above number of atoms of C, N and O, on the so-called "chart Bachman" (P. K. Bachmann et al. "Towards a general concept of diamond chemical vapour deposition", Diamond and Related Materials, 1 (1991), 1-12), isothermal section of a modified ternary phase diagram. Although the original chart Bachman has advantages, the inventors found that the use of the isothermal section of the more traditional C-H-O ternary phase diagram, which delayed atomic fraction of C, N and O, more useful (Fig. 1). In Fig. 1 the upper and lower p is Adeli H fmarked (2) and (4) respectively, the upper and lower limits of Cfmarked (6) and (8) respectively, and upper and lower limits Ofmarked (10) and (12). Therefore, the shaded region (14) in Fig. 1, these limited sets upper and lower limits, specifies the composition of the gas source of the present invention.

Using the ternary phase diagram shown in Fig. 1, the atomic structures can be compared regardless of the molecular source of atomic particles; this is especially important for processes of plasma CVD, where the particles in the plasma are essentially in thermodynamic equilibrium in the calculation of the atomic fraction of atoms present, regardless of the molecular sources of these atoms.

Atomic fraction of carbon, hydrogen and oxygen represent the proportion of the total number of atoms of carbon, hydrogen and oxygen present in the gas source, and, therefore, satisfy the relation Cf+Hf+Of=1 regardless of whether any other particles (e.g., inert gases).

The ratio of Cf:Oflies in the range of 0.45:1<Cf:Of<a 1.25:1, alternative 0,50:1<Cf:Of<1,20:1, the alternative of 0.55:1<Cf:Of<1,15:1.

Alternatively, the ratio of Cf:Ofmay be in the range of 0.54:1<Cf:Of<1,20:1, the alternative of 0.61:1&l; Cf:Of<1,18:1 alternative to 0.72:1<Cf:Of<1,15:1.

Examples of compositions that satisfy the criteria described in the examples.

The surface of the substrate on which synthesize synthetic CVD diamond material, referred to as the surface of the growth substrate. The surface of the synthetic CVD diamond material, which is attached to the surface of the growth substrate during growth, called "side substrate" (also known as the "party of nucleation, face nucleation" or "base surface"). The surface of the synthetic CVD diamond material, essentially parallel side nucleation, on which is deposited an additional CVD diamond material during the synthesis of CVD diamond material, known as "growing side" (also known as "rising edge" or "surface growth").

This substrate may be a diamond substrate, suitable for use in homoepitaxial the synthesis of diamond. Therefore, the substrate can be a natural diamond type Ia, type IIa or type IIb, WDVT-synthetic diamond type Ib or type IIa or CVD synthetic diamond. The substrate synthesized by the method of CVD diamond can be single-crystal CVD diamond, which can also be homoepitaxially (also known here as homoepitaxially podlog is). Therefore, the substrate itself may be synthesized on the source substrate.

The diamond substrate may have a surface growth (001), which is the main face of the substrate, and may be limited by edges lying essentially along directions <100>. The substrate may also have a surface growth with normal, which lies in the range of about 10° from the direction [001], alternatively in the range of about 5° from the direction [001], alternatively in the range of about 4° from the direction [001], alternatively in the range of about 3° from the direction [001]. The edges of the substrate can be in the range of about 10° from the directions <100>, alternatively in the range of about 5° from the directions <100>, alternatively in the range of about 3° from the directions <100>. The edges of the substrate can be in the range of about 10° from the direction <110>, alternatively in the range of about 5° from the direction <110>, alternatively in the range of about 3° from the direction <110>. The surface of the growth substrate can be essentially a surface{001}, {101}, {113}, {311} or {111}, and usually the surface of the {001}.

The following agreement applies to the crystallography of the diamond to be able to distinguish the surface of the growth substrate from the other surface. As applied here, for a typical substrate having the shape of a rectangular parallelepiped (for which all faces nominally ablauts the part of the form {100}) with two opposite large and four smaller faces, and opposite large faces are the faces (001) and(001-)(collectively the {001}), the surface on which growth occurs, must be a surface (001). The direction of growth, therefore, is the [001]direction, and the edge of the substrate parallel to the directions [100] and [010].

Used here, the expression "essentially", when it refers to direction, such as crystallographic direction or direction relative to the surface of the growth substrate means in the range of about 10° from the above-mentioned direction, alternatively in the range of about 5° from the above-mentioned direction, alternatively in the range of about 4° from the above-mentioned direction, alternatively in the range of about 3° from the above directions.

To obtain high-quality CVD diamond material, it is important that the surface growth of the diamond substrate was essentially free of crystalline defects. In this context, crystalline defects mean, mainly, dislocations and cracks, but also include twin boundaries, stacking faults, point defects, diskografie boundaries and any other violations of the crystal lattice.

The nature of the defects responsible for the brown CEE is diamond not entirely clear at present, but the inventors consider that it is associated with the presence of mnogovershinnyi clusters, which grow at high rate of growth, followed by the addition of nitrogen to the plasma by hydrogen/methane (H2/CH4natural gas source. These clusters are thermally unstable and can be removed to some extent, although often not fully, by high-temperature processing (i.e. annealing). It is believed that the smaller associated with vacancy defects, such as defects NVH (nitrogen-vacancy-hydrogen), which is formed from nitrogen and hydrogen and missed a carbon atom may be partially responsible for the brown color, and these defects can be removed by high temperature processing.

The density of defects are most easily characterized by optical determination after use, showing a plasma or chemical etching (referred to collectively as "manifesting etching"). Showing etching will be optimized for the manifestation of defects in the diamond substrate and may be a short anisotropic plasma etching described below type. Usually can be identified two types of defects:

1) the defects inherent in the material quality of the diamond substrate. In selected substrates from natural diamond density of these defects may be so low to the 50/mm 2more typical value of 102/mm2although other diamond materials, the density of these defects can be 106/mm2or more;

2) defects resulting from polishing, including dislocation structure and microcracks in the form of vibration cracks" along the lines of polishing. The density of these defects can vary significantly across the sample, with typical values in the range of from about 102/mm2to more than 104/mm2in a poorly polished areas or substrates.

Therefore, the preferred low density of defects is such that the density characteristics of the etching surface, attributed to the defects as described above, is below 5×103/mm2and may be below 102/mm2.

The level of defects on and below the surface of the diamond growth substrate can be minimized by careful preparation of the substrate. This training includes any process applied to the substrate material from the extraction from the mine (in the case of natural diamond) or synthesis (in the case of synthetic diamond material), since each stage can affect the density of defects within the material of the substrate on a plane that will eventually form the surface of the growth substrate, when the processing of the substrate is completed. Specific processing steps can locate in its usual diamond processes, such as mechanical sawing, conditions, lapping and polishing, and less conventional methods, such as laser processing or ion implantation methods and inverse lithography, chemical/mechanical polishing, and chemical methods of processing fluid and plasma. In addition, the surface roughness described by its magnitude Rashould be minimized; typical values prior to any plasma etching amount to a few nanometers, i.e. of 10 nm or less.

Ra(sometimes referred to as "RA"or "average from the center line", or "c.l.a.") refers to the average of the absolute deviations of the measured supovym profilometer surface profile from the mean line measured along the length of 0.08 mm and measured according to British standard BS 1134 Part 1 and Part 2. The mathematical description of Ra(from "Tribology", I.M. Hutchings, Pub. Edward Arnold (London). 1992, pages 8-9) represents:

Ra=1L0L|y(x)|dx

(the arithmetic average of the absolute deviations of the surface profile measured supovym profilometer, typically at a length of 0,m). Dimension Rausing supalogo Profiler is well known in the art, and there are many tools that are suitable for performing such measurements; for example, the inventors used a Taylor Hobson FormTalysurf 50", (Taylor Hobson Ltd, Leicester, UK).

Damage to the surface of the diamond growth substrate can be minimized by providing an anisotropic etching, such as plasma etching.

Anisotropic etching includes removing material from the surface of the growth substrate to provide a surface growth, which is essentially flat and is free or essentially free from residual signs of damage arising from any of the previous processing steps, particularly steps of machining.

Anisotropic plasma etching may be oxygen etching using etching gas containing hydrogen and oxygen. Alternatively, plasma etching may be hydrogen etching. In an additional alternative to plasma etching may also contain oxygen, and hydrogen etching, and in some cases for the oxygen etching should hydrogen etching. Beneficial to hydrogen etching followed by oxygen etching, since the hydrogen etching is less specific to the crystalline defect and round out any uncouthness, caused by oxygen etching (which has an aggressive effect on such crystalline defects), and provides smooth, the best surface of the growth substrate.

The duration and temperature of the anisotropic plasma etching choose to allow to delete any damage to the substrate surface and to remove any surface impurities. The surface of the substrate may be damaged by the processing steps performed before plasma etching. In General, plasma etching does not form vysokoprohodimoy surface on the substrate and not Watervliet intensively along extended defects (such as dislocations)that intersect the surface and, thus, cause a deep fossa.

Anisotropic etching can be insitu plasma etching. In principle, this etching is not required to be insitu or immediately before the synthesis of the diamond material, but the greatest advantage is achieved if it is insitu, as it eliminates any danger of further physical damage or chemical contamination of the substrate. Etching insitu is also usually the most convenient, when the synthesis of the diamond material is also based on the plasma. Plasma etching may be used conditions similar to those used for the synthesis of diamond material, but in the absence of any of carbon is containing gas source, and usually at a slightly lower temperature, in order to have better control of the etching rates.

Conditions anisotropic oxygen etching may be pressure from about 50×102PA to about 450×102PA, etching gas having an oxygen content from about 1% to about 4%, the content of argon is approximately 30% or less and the rest of the hydrogen, all percentages are by volume, the temperature of the substrate from about 600°to about 1100°C. (typically about 800°C) and duration of etching from about 3 minutes to about 60 minutes.

Conditions anisotropic hydrogen etching may be pressure from about 50×102PA to about 450×102PA, the etching gas containing hydrogen and about 30% or less of argon by volume, the temperature of the substrate from about 600°to about 1100°C. (typically about 800°C) and duration of etching from about 3 minutes to about 60 minutes.

Can be used for alternative methods of etching, is not based solely on argon, hydrogen and oxygen, for example, methods that use halogen-free, other inert gases or nitrogen.

Over the duration of the synthesis process, the substrate can be maintained at a temperature of from about 750°to about 1000°C., alternatively from about 750°to about 950°C., alternatively from about 780°C. to about 870°C.

Used herein, the term " environment "synthesis" means a portion in which trojstva synthesis, which is the synthesis of CVD diamond material. This is usually the area below on the go from the gas supply system, and up along the way from controls pressure in the synthesis medium, for example a throttle valve that regulates the flow resistance of the gas, and the vacuum pump. Wednesday synthesis contains a gas source, and any gases due to leakage, reverse-leakage through the vacuum pumps and desorption from the device synthesis. Therefore, changes in the composition of the gas source provided by the gas supply system, affect the composition of the gas environment of the synthesis. However, the composition of the gas in the environment of synthesis also depends on other factors, such as the synthesis process. In principle, the gas supply system can have more than one entry point in the synthesis, so that the composition of the gas source provided by the gas supply system, there is no pre-mixed within the gas supply system, and is determined by the relative flows of gases added to the environment of the synthesis gas supply system.

All links here on the composition of the gas in the environment of the synthesis is based on the amount of gas added to the environment of the synthesis gas supply system and any gas due to leakage, reverse-leakage through the vacuum pumps and desorption from the device synthesis. It can be determined by activating the gas supply system, a gas supply source in the synthesis system, where Bud is t leaking synthesis of CVD diamond material, and at this point will also be generated for any gases due to leakage, reverse-leakage through the vacuum pumps and desorption from the device synthesis. The composition of the gas in the environment of the synthesis can be then defined in the system synthesis, where will be the synthesis of CVD diamond material, without real synthetic CVD diamond material.

Gas concentration in the environment of synthesis is regulated by changing the concentration of the gas in the gas source to the gas inlet of the primary device synthesis. Therefore, the measurement of concentrations of gases in gas-source composition was determined by gas-source before it is introduced into the device synthesis, and were not measured in the environment of the synthesis in situ (i.e. within the device synthesis). Specialist in the art will be able to calculate the required flow of any individual gases that will be needed to provide the desired concentration in the gas source.

Wednesday synthesis contains nitrogen in an atomic concentration of from approximately 0.2 h/m to about 100 hours/million, alternatively from about 0.5 hours/million up to about 50 hours/million, alternatively from about 1 h/m to about 30 hours/million, alternatively from about 2 hours per million up to about 20 hours/million, alternatively from about 5 o'clock/m to about 20 hours/million Preferably, the atomic nitrogen content in the environment of the synthesis is from about 5 o'clock/m to PR is approximately 20 hours/million The nitrogen concentration can be defined as the atomic fraction of nitrogen, N, all gas flow gas source; for example, the gas flow 1000 SMS3(standard cubic centimeters) H2and 150 SMS3H2containing 100 hours/million N2will have the atomic nitrogen content of:

(150×100×2)/(1000×2+150×2)=13 hours/million

Nitrogen in the environment of the synthesis can be achieved with nitrogen (i.e. N2or nitrogen-containing gases (such as ammonia (NH3), hydrazine (N2H4) and others).

The method according to the present invention further comprises the dissociation of the gas source. The dissociation of the gas source in the environment of synthesis is called a source of energy, such as microwave, RF (radio frequency) energy, flame, hot thread or ink-jet method, and thus obtained reactive gas particles (also referred to here as the "plasma") provide an opportunity to settle on the surface of the growth substrate and to form the synthetic CVD diamond material. In one embodiment, the implementation of the energy source is a microwave energy source. The frequency of the microwave source can be from about 800 MHz to about 2500 MHz, such as from about 800 MHz to about 1000 MHz, and is typically one of the industrial frequency heating, examples of which include 2450 MHz, 915 MHz and 896 MHz.

The method according to the present invention can be the ü carried out at a pressure of about 8000 PA (60 Torr) or more, alternative approximately 10600 PA (80 Torr) or more, alternatively about 13300 PA (100 Torr) or more, alternatively about 16000 PA (120 Torr) or more.

The method according to the present invention can be carried out at a pressure of from about 10600 PA (about 80 Torr) to about 40000 PA (about 300 Torr), alternatively from about 12,000 PA (about 90 Torr) to about 40000 PA (about 300 Torr), alternatively from about 13300 PA (about 100 Torr) to about 40000 PA (about 300 Torr), alternatively from about 10600 PA (about 80 Torr) to about 26600 PA (approximately 200 Torr), alternatively from about 12,000 PA (about 90 Torr) to about 24000 PA (about 180 Torr), alternatively from about 13300 PA (about 10 Torr) to about 20000 PA (150 Torr). The method according to the present invention unexpectedly allows the use of these high pressure in combination with a gas source containing O-containing sources, making possible more efficient etching of non-diamond carbon and defects, as discussed above, thereby providing a synthesis of high-quality CVD diamond material.

In one embodiment, the implementation of the method according to the present invention can be carried out at a pressure of from 13300 PA (100 Torr) up to 40,000 PA (300 Torr).

The inventors have discovered that there is a pressure Parcabove which there is a greatly enlarged opasnost the formation of monopolar arcs in the plasma, to interrupt or stop the process of synthesis, which is associated with the atomic fraction of hydrogen (Hfin gas-source. The inventors have found that Parcspecified as:

Parc=170(Hf+0,25)+X,

where the units of Parcare Torr (1 Torr=133,3 PA). Although this equation gives Parcmeasured in Torr, a specialist will know how to convert it to a measurement in Pascals. X reflects the fact that this upper limit pressure may change slightly depending on the configuration of the reactor and process conditions other than Hfbut for any given reactor and process simple experience can be set, where this limit by changing the pressure and observing the pressure of formation of unipolar arcs. The inventors have found that X is usually in the range of from about 20 to about -50; alternatively, from about 20 to about -30; alternatively, from about 10 to about -30; alternatively, from about 20 to about -20; alternatively, from about 10 to about -20; alternatively, from about 10 to about -10; alternatively, from about 5 to about -10; alternatively, from about 5 to about-5. Alternatively, X may be about 10, alternatively about 5, about alternative 0 alternative approximately -5, alternative approximately-10.

Defining the value of X, it was found that it you agenie remains valid in the range of values of H fbetween approximately 0.4 and approximately 0,95 (for example, between about 0.4 and about 0.75) and for a wide range of Cfand Ofconstituting the balance of the synthesis medium. In addition, the inventors discovered that the addition of one or more inert gases in nuclear fractions, as described previously, no significant effect on the limit pressure Parc.

The inventors have found that the preferred operating pressure in the method according to this invention exceeds Plowerwhere Plower=Parc-Y, where the units of Plowerand Y are Torr, and the value of Y is about 50 Torr or less, alternatively about 40 Torr or less, alternatively about 30 Torr or less, alternatively about 20 Torr or less, alternatively about 10 Torr.

In one embodiment, the implementation of the method according to the present invention is carried out at a pressure PlowerTorr, where Plower=Parc-Y, and Parc=170(Hf+0,25)+X, where Y is about 50 Torr, X is about 0 Torr and Parcrepresents the pressure at the beginning of the formation of unipolar arc in the process.

Working pressure may be about 120 Torr or more, alternatively about 130 Torr or more, alternatively about 140 Torr or more, alternatively about 150 Torr or more, alternatively about 160 Torr or more. These working pressure may be applied, when Hfequal to 0.75.

The preferred operating pressure lies at or below the Parcand because of the stability of the process is preferably small, but significant pressure below Parc. This pressure is denoted as "Pupper" and is measured in Torr.

Thus, the inventors have found that the preferred operating pressure in the method according to this invention is defined as Pupper=Parc-Z, where Z is about 0 Torr, alternative Z is about 5 Torr, alternative Z is about 10 Torr.

Specialist in the art will understand that any of the above values of X, Y and Z can be combined.

In one embodiment, the implementation of the method according to the present invention is carried out at a pressure less than or equal to Pupperwhere Pupper=ParcZ and Parc=170(Hf+0,25)+X, where X is from about 20 to about -50, Parcrepresents the pressure at the beginning of the formation of unipolar arcs in the process, and Z is about 0 Torr.

In one embodiment, the implementation of the method according to the present invention is carried out at a pressure less than or equal to Pupperwhere Pupper=ParcZ and Parc=170(Hf+0,25)+X, where X is about 0, Z is about 0 Torr and Parcrepresents the pressure at the beginning of the formation of the unipolar dpiv process.

Working pressure Puppermay be about 170 Torr or less, alternatively about 165 Torr or less, alternatively about 160 Torr or less. These working pressure can be applied when Hfequal to 0.75.

As mentioned previously, the present invention provides synthetic CVD diamond material containing Ns0concentration of greater than about 0.5 hours/million (approximately 8,8×1016atoms per cm3and with this total integrated absorption in the visible region from 350 nm to 750 nm, at least about 35% of the absorption is attributed to the Ns0.

Alternatively, the concentration of Ns0in the synthetic CVD diamond material may be more than about 1.0 hours/million, an alternative more about 1,5 hours/million, an alternative more about 1.8 hours/million, an alternative more roughly 2.0 hours/million, an alternative more about 2,5 hours/million, an alternative more about 3,0 hours/million, an alternative more than about 3.5 hours/million, an alternative more than about 4.0 hours/million, an alternative more about 5,0 hours/million, an alternative more about to 7.0 hours/million, an alternative more about 10,0 hours/million, an alternative more about 15,0 PM/million, an alternative more about 20,0 hours/million, an alternative more about 25,0 hours/million, an alternative more about 50,0 hours/million, an alternative more about 75,0 h/million, the alternative is actively more about 100.0 hours/million

Preferably, the concentration of Ns0approximately 200 hours/million or less.

Preferably, the concentration of Ns0in the synthetic CVD diamond material is more than about 1.0 hours/million and less than about 25 hours/million, an alternative more about 2,0 h/m and less than about 15 hours/million

This diamond is a diamond material is a semiconductor with a wide band gap, and, in particular, the diamond material containing defects, not necessarily a well-defined Fermi level. At room temperature (i.e. about 300 K) charge, which the original captured on the defect with an energy level that is relatively small compared with either the maximum of the valence band, or with a minimum of the conduction band, will reach an equilibrium distribution through transfer after thermal excitation in the valence or the conduction band. However, the diamond material may contain defects with energy levels that are relatively deep inside the forbidden zone, so that at room temperature there is a low probability that the electrons will be thermally excited between the valence band and the defect or between the defect and the conduction band. When such defects are present, the distribution of charge time among the ranks of defects may depend on thermal history and prehistory of the excitation of the sample. In such cases, the extent to which the optical absorption properties of the material depend on the state of charge of defects inside it, they will also depend on thermal history and prehistory of the excitation of the sample. For example, the proportion of isolated substitutional nitrogen defects that exist in the neutral charge state may depend on the previous thermal history and prehistory of the excitation of the sample, and hence the fraction of the total optical absorption, which is attributed to this neutral defect, will also depend on the prehistory of the sample.

For the avoidance of doubt, when the background pattern is not specified, the properties of the material described in this invention, should be understood as properties that can be measured at room temperature (i.e. about 300 K) without additional excitation of the sample during measurement, other than that required for the measurement.

Preferably, the properties measured after the sample was irradiated with light from the deuterium lamp under the following conditions:

(a) the distance between the sample and the lamp is approximately 10 cm or less;

(b) the lamp operates with an electrical power of at least 10 Watts; and

(C) duration of between about 5 minutes and about 60 minutes.

In particular, the properties of eraut after as the sample was irradiated by light of a deuterium lamp under the following conditions:

(d) the distance between the sample and the lamp is 8 cm;

(e) the lamp operates at an electric power of 10 Watts; and

(f) the duration of 10 minutes.

Deuterium lamp (also known as deuterium arc lamps") are widely used in spectroscopy, where required continuous output wavelength between about 180 nm and about 370 nm.

The concentration of Ns0present in the synthetic CVD diamond material of the present invention, can be measured using the peak at 270 nm using absorption spectroscopy in the UV-visible region. The method of absorption spectroscopy in the UV-visible region is well-known in this technical field.

The concentration of Ns0in the synthetic CVD diamond material can be found by measuring the infrared absorption peaks at wave numbers 1332 cm-1and 1344 cm-1. When using a spectrometer with a resolution of 1 cm-1conversion between the values of the absorption coefficient in cm-1for peaks 1332 cm-1and 1344 cm-1and concentrations of single nitrogen is positively charged and neutral conditions, respectively 5.5 (S. C. Lawson et al., J. Phys. Condens. Matter, 10 (1998), 6171-6181) and 44. However, it should be noted that the value obtained is from the peak 1332 cm -1is only an upper limit.

Alternatively, the total concentration of nitrogen can be determined using mass spectroscopy secondary ion (SIMS). SIMS has a lower detection limit for nitrogen in diamond approximately 0.1 hours/million, and its use is well known in the art. For synthetic diamond, obtained CVD method, the vast majority of the nitrogen present in the solid is in the form of neutral single substitutional nitrogen, Ns0and therefore, although SIMS measurements of the total concentration of nitrogen inevitably provide the upper limit of the concentration of Ns0they usually also provide a reasonable estimate of its actual concentration.

Alternatively, the concentration of Ns0can be determined using electron paramagnetic resonance ("EPR"). Although this method is well known in the art, for completeness, it is summarized here. When the measurements are performed using EPR, the number of specific paramagnetic defect (for example, defect neutral single substitutional nitrogen, Ns0) proportional to the integrated intensity of all the resonance absorption lines of the EPR originating from this center. This allows to determine the concentration of the defect by comparing this Integra is Inoi intensity with the which is observed from the comparison sample, subject to the adoption of measures for the prevention or correction of saturation effects of microwave energy. As continuous wave EPR spectra were recorded using a field modulation, requires double integration to determine the EPR intensity and, consequently, the concentration of defects. To minimize errors associated with double integration, baseline correction, the ultimate limits of integration, and so on, especially in cases when there is an overlap between the EPR spectra of the method is a spectral smoothing (using the simplex algorithm of Nelder-Mead (J. A. Nelder and R. Mead, The Computer Journal, 7 (1965), 308)) to determine the integrated intensity of the EPR centers present in any sample. This entails fitting the experimental spectra to simulated spectra of defects present in the sample, and determining the integrated intensity of each simulation. Experimentally observed that neither Lorentz nor the Gaussian shape of the curve does not provide a good fit of the experimental EPR spectra, therefore, to obtain the simulated spectra function is used Callis (D.F. Howarth, J.A. Weil, Z. Zimpel, J. Magn. Res., 161 (2003), 215). In addition, in the case of low concentrations of nitrogen is often necessary to use amplitude modulation approaching and exceeding the line width of the EPR signals, in order to achieve a good signal-to-noise ratio (allowing accurate determination of the concentration within an acceptable time frame). So use pseudomaculata with the shape of the curve Callisa to get a good fit to the recorded EPR spectra (J.S. Hyde, M. Pasenkiewicz-Gierula, A. Jesmanowicz, W.E. Antholine, Appl. Magn. Reson., 1 (1990), 483). Using this method, the concentration may be determined with a reproducibility of better than ±5%.

Specialist in the art will be able to determine which method of measurement of Ns0will be suitable for use in any given situation.

The specialist is familiar with the methods that can be used to distinguish between synthetic CVD diamond and synthetic VDT diamond. The subsequent is a series of non-limiting examples of these methods.

One method to distinguish synthetic CVD diamond material from synthetic diamond material synthesized using VDT methods based on the structure of dislocations. In the synthetic CVD diamond dislocation usually take place in a direction that is approximately perpendicular to the original surface of the growth substrate, i.e. when the substrate is a substrate (001), dislocations approximately aligned parallel to the [001]direction. In synthetic diamond material synthesized using VDT methods, dislocation,which arise on the surface of embryonic crystal (often surface, close to {001}), usually grow in the direction <110>. Thus, these two types of material can be distinguished by their different observed dislocation structures, for example, when x-ray topography. However, obtaining x-ray topographs is a difficult task and would be clearly desirable alternative, less time-consuming method, which allows to make a confident distinction.

An additional way to distinguish between synthetic CVD diamond material from synthetic diamond material synthesized using VDT methods, based on the presence of metallic impurities in VDT-synthesized material, which is embedded in the process of synthesis. These inclusions consist of metals used as the catalytic metal-solvent, such as Fe, Co, Ni and other Inclusions can vary in size from less than 1 micron to over 100 microns. Large inclusions can be observed using a stereomicroscope (e.g., Zeiss DV4); whereas smaller inclusions can be observed using transmitted light in metallurgical microscope (e.g., Zeiss Axiophot").

An additional method that can be used to ensure a confident difference between synthetic diamonds obtained by CVD and WDT ways, is a photoluminescence spectrum of the scopy (PL). If WDT-synthesized diamond often present defects containing atoms of catalytic metals (usually transition metals)used in the synthesis process (for example, Ni, Co, Fe, and other), and detection of such defects using fluorescence surely indicates that this material was synthesized using UDWT method.

Defects related to the presence of atoms of catalytic metals in diamond is an advantage of the diamond obtained by the present invention, the material obtained by VDT ways, because such defects can locally disrupt the Fermi level, affecting the suitability of the material for use as a substrate for the manufacture of electronic devices such as field effect transistors (FET).

Synthetic CVD diamond material of the present invention can be identified by its unique integral absorption and its relationship with Ns0. The integral absorption is measured using the absorption spectrum of synthetic CVD diamond material in the UV/visible region, obtained at room temperature. All absorption spectra, referred to here were obtained using a spectrometer Perkin Elmer Lambda-9. Absorption spectra of the diamond material in the UV/visible region may exhibit characteristic bands at 360 nm and 510 nm.

The data C is written in the spectra (measured spectrum), were subjected to deconvolution in the following way : getting information about the proportion of the measured absorption, which can be attributed to Ns0and the proportion of the measured absorption, which can be attributed to other defects.

(a) spectrum of the reflection losses created using tabular data on the refractive indices and the standard expressions for the reflection losses at the plate with parallel sides

b) the Range of reflection losses subtracted from the measured values of the absorption and of the resulting spectrum has created a range of absorption coefficient.

(C) to determine the component of the measured spectrum, which is attributed to the Ns0, absorption spectrum for VDT synthetic diamond type Ib (for which the absorption is attributed only Ns0) has scaled up until essentially did not remove the peak at 270 nm from the measured spectrum by the subtraction from it.

d) Using the visible region of the spectrum ranging from 380 nm (i.e. 3,2618 eV) to 750 nm (i.e. 1,6527 eV), the integrated absorption in the visible region were determined for the measured spectrum (C) and its components, attributed to Ns0(In). Can then be calculated ratio of the integrated absorption in the visible region attributed to Ns0components and the measured spectrum (In/S). The contribution of the optical pohlad the deposits in the visible region is not due to N s0specifies the size-Century

e) In practice, the losses are usually higher than theoretical values, and this can complicate the determination of absolute values of the absorption coefficient. To adjust for the additional losses that are not directly related to the absorption, used the following procedure. In relation to lower energies it was usually the case when lower specific energy measured absorption did not show significant changes with energy. Data on the absorption coefficient was shifted so that the absorption coefficient was zero on the energy at which no further significant changes of the absorption coefficient.

The remaining spectrum was further subjected to deconvolution in the component proportional to 1/λ3and two overlapping bands, one centered at 360 nm, and the other centered at 510 nm. The specialist will understand how to calculate the absorption coefficients in these bands.

Synthetic CVD diamond material of the present invention can be fully integrated absorption in the visible region from 350 nm to 750 nm, at least about 35%, alternatively at least about 40%, alternatively at least about 45%, alternatively at least about 50%, alternatively at least about 55%, alternatively, less is th least about 60%, alternatively at least about 65%, alternatively at least about 70%, alternatively at least about 75%, alternatively at least about 80%, alternatively at least about 85%, alternatively at least about 90%, alternatively at least about 92%, alternatively at least about 94%, alternatively at least about 96%, alternatively at least about 98%, alternatively at least about 99% of the integrated absorption (eV·cm-1) is attributed to the Ns0.

Preferably, the synthetic CVD diamond material of the present invention, at least about 85% of the integrated absorption between 350 nm and 750 nm is attributed to the Ns0.

These values are integral absorption indicate that the synthetic CVD diamond material of the present invention is similar to the diamond with its own conductivity, with high-quality color, and that this is due to the lower concentration of other defects than the Ns0that absorb in the visible part of the spectrum. This shows that synthetic CVD diamond material of the present invention is of high quality.

Synthetic CVD diamond material of the present invention can also be characterized with the help of the it spectrum, photoluminescence (PL). They are usually obtained by excitation with a laser source generating a continuous mode using a power between about 10 mW and approximately 100 mW, focused on the surface of the diamond sample using a microscopic lens, and detection using a diffraction spectrometer high resolution (better than about 0.5 nm). At 77 K, using 488 nm excitation from an argon ion laser, the fluorescence spectrum of synthetic CVD diamond diamond according to the present invention shows a peak between about 543,0 nm and about 543,2 nm with respect to the intensity of this peak, normalized to the Raman line diamond 1-th order (if 521,9 nm for the wavelength of excitation), which is more about 0,005. The inventors believe that the peak between about 543,0 nm and about 543,2 nm is associated with the presence of oxygen in the synthesis process with the nuclear share of at least approximately 0.05 relative atomic fraction of carbon, as this peak was observed only in these circumstances. At 77 K, using 488 nm excitation from an argon ion laser, the fluorescence spectrum of synthetic CVD diamond diamond of the present invention also shows a second peak between about 539,9 nm and about 540,1 nm. This peak is usually between 1/8thand 1/12ththe intensity of the peak is between 543,0 nm and 543,2 nm and therefore is observed only when in the environment of synthesis there is a significant atomic fraction of oxygen. The composition and structure of the defects responsible for either peak between about 543,0 nm and about 543,2 nm or peak between about 539,9 nm and about 540,1 nm, is not clarified yet. It is possible that these two peaks are visible in the synthetic CVD diamond material of the present invention, are interrelated.

Synthetic CVD diamond material of the present invention may also be specified using its fluorescence spectrum when using 514.5 nm excitation argon ion laser. When using this type of excitation fluorescence spectrum of synthetic CVD diamond material of the present invention shows two peaks in the photoluminescence, the first peak at 574,8-575,1 nm (approximately 575 nm) and the second peak at 636,9-637,1 nm (approximately 637 nm), so that the ratio of the integral intensity of the peak 637 nm to 575 nm peak intensity greater than about 1.0, alternatively greater than about 1.2, alternatively greater than about 1.4. Not wishing to be bound by theory, the first and second peaks of the spectrum, fluorescence correspond to the defect nitrogen-vacancy in its neutral and negatively charged States, respectively.

Furthermore, the material according to the present invention shows a marked decrease in the level of the individual line 737 nm, which is related to the defect of the silicon Islands is Asia (Si-V). It is believed that the decrease in the fluorescence line 737 nm occurs in the absence of special reduce the concentration of silicon in the environment of the synthesis, and therefore, the inventors believe that this decrease is caused not yet identified the change of the injection mechanism of silicon.

Using photoluminescence (PL) spectroscopy for characterization of defects in diamond is well known in the art. In fluorescence in the sample exposed to the photons of a specific wavelength (for example, 514.5 nm radiation from an argon ion laser). It excites the electrons in the material to higher energy levels. The excited electrons move back to their basic state and emit photons having wavelengths that are characteristic of this transition and which can be characterized using the spectrometer. On sale there are numerous fluorescence spectrometers.

Synthetic CVD diamond material of the present invention can implement the ratios IR absorption over (i) 0.1 cm-1at 1332 cm-1and (ii) of 0.05 cm-1at 1344 cm-1when using an infrared absorption spectrometer with a resolution of 1 cm-1. They respectively indicate that the concentration of a single nitrogen is (i) greater than 0.55 ppm in the positive charge state and (ii) more than 2.2 parts per million in neutral for Agawam condition. The correlation between the absorption coefficient at 1332 cm-1and single substitutional nitrogen in the neutral charge state is such that the absorption coefficient of 1 cm-1corresponds to approximately 5.5 hours/million Correlation between the absorption coefficient at 1344 cm-1and single substitutional nitrogen in the positive charge state is such that the absorption coefficient of 1 cm-1approximately 44 hours/million

Synthetic CVD diamond material of the present invention can have at least about 50%, alternatively at least about 80%, alternatively at least about 90%, alternatively at least about 95% of the volume of synthetic CVD diamond material formed from a single sector growth. Material from a single sector growth can have levels of Ns0within ±10% from the average of more than about 50% of the total sector growth, alternatively more than about 60% of the total sector growth, alternatively more than about 80% of the sector's volume growth. The formation of the synthetic CVD diamond material of a single sector growth is beneficial, since CVD diamond material will have less of surfaces with different crystallographic orientations (which are the surfaces corresponding to different growth sectors). Surfaces with different Chris is allopaticakimi orientations show a much different absorption of impurity nitrogen, and so synthetic CVD diamond material tends to have an undesirable areas of different color, resulting from different concentrations of Ns0in different growth sectors. Therefore, the use of a single sector growth will lead to synthetic CVD diamond material of higher quality.

Synthetic CVD diamond material of the present invention may contain other impurities than the Ns0. In one embodiment, the implementation of the elemental concentration of individual chemical impurities other than nitrogen and hydrogen is less than about 0.1 hours/million, alternative less than approximately 0.05 h/mn, alternative less than approximately 0.02 hours/million, alternatively less than about 0.01 of hours/million Used herein, the terms "elemental concentration" means the absolute chemical concentration mentioned impurities.

The concentration of substitutional boron may be about 1×1017atoms per cm3or less, alternatively about 5×1016atoms per cm3or less, alternatively about 1×1016atoms per cm3or less. The concentration of hydrogen (including hydrogen isotopes) can be about 1×1019atoms per cm3or less, alternatively about 1×1018atoms per cm3or less, alternatively about 1×1017atoms per cm3or less.

Perceive the color of an object depends on the spectrum transmittance/absorption of the given object the spectral energy distribution of the light source and the response curves of the eye of the observer. The chromaticity coordinates CIE L*a*b (and, therefore, the angles of the colour tone), presented here, were obtained as described below. Using standard D65 spectrum lighting and standard (red, green and blue response curves of the eye (G. Wyszecki and W.S. Stiles, John Wiley, New York-London-Sydney, 1967), chromaticity coordinates CIE L*a*b plate with parallel sides of the diamond were obtained from its spectrum bandwidth, using the following correlations between 350 nm and 800 nm with a data interval of 1 nm:

Sλ= transmittance at wavelength λ,

Lλ= the spectral energy distribution of light,

xλ= the function of the red response of the eye,

yλ= the green function of the response of the eye,

zλ= function blue response of the eye,

X=Σλ[SλxλLλ]/ Y0,

Y=Σλ[SλyλLλ]/ Y0,

Z=Σλ[SλzλLλ]/Y0,

where Y0λyλLλ,

L*=116(Y/Y0)1/3-16 = brightness (Y/Y0>0,008856),

a*=500[(X/X0)1/3(Y/Y0)1/3] (X/X0>0,008856, Y/Y0>0,008856),

b*=200[(Y/Y0)1/3-(Z/Z0)1/3] (Z/Z0>0,008856),

C*=(a*2+b*2)1/2= saturation

hab=rctan(b*/a*) = angle hue.

Modified versions of these equations should be used outside Y/Y0X/X0and Z/Z0. Modified versions are given in the technical report prepared by the Commission Internationale de L'éclairage (Colorimetry (1986)).

Usually lay coordinates a* and b* on the graph, where* corresponds to the x-axis, and b* corresponds to the y-axis. Positive values of a* and b* correspond to the red and yellow components of the color tone. Negative values a* and b* correspond to the green and blue components. Positive quadrant of the graph covers then the hues range from yellow through orange to red, and saturation (C*) are given by the distance from the origin.

You can predict how a*b* coordinates of the diamond with the spectrum of the absorption coefficient will change with a change in optical path length. To do this, you first need to subtract the losses from the measured absorption spectrum. Absorption then scale, taking into account the different path length, and then add back loss. Absorption spectrum can then be converted in the transmission spectrum, which is used to obtain the coordinates of the CIE L*a*b* for the new thickness. Thus, the dependence of the hue, saturation, and brightness from the optical path length can be modeled to understand how color diamond with the data and properties of absorption per unit thickness will depend on the optical path length.

The brightness L* forms a third direction color space CIE L*a*b*. It is important to understand that how the brightness and saturation change an optical path length changes for the diamond specific properties of optical absorption. This can be shown on the chart color tones, where L* pending on the y-axis, and* deferred on axis X. Described in the previous paragraph, the method can also be used to predict how L*S* coordinates diamond with the spectrum of the absorption coefficient depends on the optical path length.

The value of C* (saturation) can be divided into intervals of saturation by 10 units* and called descriptive terms below.

0-10 weak

10-20 weak - moderate

20-30 moderate

30-40 moderate - strong

40-50 strong

50-60 strong - very strong

60-70 is very strong

70-80+ very strong

Similarly, the values of L* can be divided into intervals of brightness as follows:

5-15 very dark

15-25 very dark

25-35 dark

35-45 medium/dark

45-55 average

55-65 light/medium

65-75 light

75-85 very bright

85-95 very bright

There are four basic hues defined by the following combinations of brightness and saturation:

bright: bright and high saturation.

pale light and the izkuyu saturation,

thick: high saturation and dark,

dim: low saturation and dark.

The hue angle of more than 80° to the length of the path bandwidth of 1 mm indicates that the color of synthetic CVD diamond material of the present invention is determined mainly Ns0with a small contribution from the other color centers in the material. In particular, synthetic CVD diamond material of the present invention, being in the form of a plate with parallel sides in the thickness of approximately 1 mm, can have the following color settings in the color space CIE L*a*b*:

a* between about -20 and about 1, alternatively between about -10 and about 1, alternatively between about -5 and about 1;

b* more than about 5 and less than about 20, alternatively more than about 10 and less than about 20;

C* (saturation) between about 0 and about 30, alternatively between about 1 and about 25, alternatively between about 2 and about 30; and

L* (brightness) of more than about 40 and less than about 100, alternatively more than about 50 and less than about 100, alternatively more than about 60 and less than about 100.

This provides a quantitative measure of the quality of the synthetic CVD diamond material of the present invention. These color properties are advantageous because they give a diamond pure yellow color and can be used for de is orationi purposes, such as precious stones for jewelry.

The diamond material of the present invention may have a hue angle for the path length of the transmission 1 mm to about 80° or more, alternatively about 85° or more, alternatively about 90° or more, alternatively about 95° or more.

CVD diamond material of the present invention may have a hue angle less than about 180° to the length of the path bandwidth 1 mm.

It is possible that synthetic CVD diamond material produced using plasma on the basis of N (for example, using gas mixtures of sources N2/CH4), included more than 0.5 hours/million Ns0but such synthetic CVD diamond material obtained with the use of these gases-sources on the basis of H2/CH4will have extremely high levels of other defects that reduce quality and appearance (or color) of the material. Therefore, the synthetic CVD diamond material of the prior art typically have a hue angle of less than about 80°, and often less than 70°, the length of the path bandwidth of 1 mm and are, therefore, dyed brown.

In one embodiment, the implementation of the synthetic CVD diamond material of the present invention may be in the form of a stand-alone object, having a thickness of more than about 0.2 mm, alternatively more than about 0.5 mm alternative than about 1.0 mm, alternative more than about 1.5 mm, alternatively more than about 2.0 mm, alternatively more than about 2.5 mm, alternatively more than about 3.0 mm, alternatively more than about 3.5 mm, alternatively more than about 4.0 mm, alternatively more than about 5.0 mm, alternatively more than about 6.0 mm, alternatively more than about 10 mm, alternatively more than about 15 mm.

In one embodiment, the implementation of the synthetic CVD diamond material of the present invention may be in the form of a stand-alone object, having a thickness less than about 50 mm; alternatively, less than about 45 mm; alternatively, less than about 40 mm; alternatively, less than about 35 mm; alternatively, less than about 30 mm; alternatively, less than about 25 mm; alternatively, less than about 20 mm

Such thickness of the independent objects made of synthetic CVD diamond material of the present invention are advantageous because they can be used in decorative applications such as precious stones for jewelry. Such objects can also be used in the diamond electronic devices, such as FET.

In another embodiment, the implementation of the synthetic CVD diamond material of the present invention may be in the form of a layer attached to the diamond with other characteristics (e.g., level of impurities, platnost the dislocations, the proportion of carbon isotopes and other). A layer of CVD diamond material of the present invention may have a thickness of approximately 0.5 mm or less, alternatively about 0.2 mm or less, alternatively about 0.1 mm or less, alternatively about 10 μm or less, alternatively about 1 μm or less, alternatively about 300 nm or less, alternatively about 100 nm or less.

In another embodiment, the implementation of the synthetic CVD diamond material of the present invention may be in the form of a layer having a thickness of about 0.1 nm or more; alternatively about 0.2 nm or more; alternatively about 0.3 nm or more; alternatively about 0.4 nm or more; alternatively, about 0.5 nm or more.

These layers are made of synthetic CVD diamond material of the present invention are advantageous because they can be used in small-scale electronic devices.

Synthetic CVD diamond material of the present invention may be in the form of a doublet. The doublet is a synthetic CVD diamond material, made of layered sections. Bottom, a large part is made of synthetic CVD diamond material of lower quality and has a smaller layer of synthetic CVD diamond material of higher quality, is attached on top of it. These doublets best as they can the ut to be used for appointments precious stones.

The present invention additionally provides a gemstone containing synthetic CVD diamond material of the present invention and/or produced by the method according to the present invention.

The present invention additionally provides for the use of synthetic CVD diamond material of the present invention and/or produced by the method according to the present invention as a precious stone.

The present invention additionally provides for an electronic device containing synthetic CVD diamond material of the present invention and/or produced by the method according to the present invention.

The present invention additionally provides a fluorescent detector, containing a layer of diamond material according to the invention, which emits photoluminescence upon irradiation by x-rays.

The present invention additionally provides for the use of synthetic CVD diamond material of the present invention and/or produced by the method according to the present invention in an electronic device.

The present invention provides synthetic CVD diamond material containing Ns0concentration of greater than about 0.5 hours/million and with such a complete integrated absorption in the visible region from 350 nm to 750 nm, h is about at least about 35% of the absorption is attributed to the N s0and this material may have one or more of the following properties:

(a) the hue angle of more than approximately 80° to the path length of the transmission 1 mm;

(b) photoluminescence spectrum at 77 K using 488 nm excitation from an argon ion laser, which shows a peak at from about 543,0 to about 543,2 nm, with the ratio of the intensity of this peak, normalized to the Raman line diamond 1-th order (if 521,9 nm for the wavelength of excitation), more than about 1/50 or, preferably, about 1/100 or, preferably, about 1/200;

(C) photoluminescence spectrum when using 514.5 nm excitation from an argon ion laser, showing two peaks in the photoluminescence, the first 574,8-575,1 nm (approximately 575 nm) and the second when 636,9-637,1 nm (approximately 637 nm), so that the ratio of the integral intensity of the peak 637 nm to 575 nm peak greater than about 1.0, alternatively greater than about 1.2, alternatively greater than about 1.4.

Therefore, in one implementation of the present invention provides a synthetic CVD diamond material containing Ns0concentration of greater than about 0.5 hours/million and with such a complete integrated absorption in the visible region from 350 nm to 750 nm, at least about 35% of the absorption is attributed to the Ns0that is rich, this synthetic CVD diamond material has the above characteristic (a).

In an additional implementation of the present invention provides a synthetic CVD diamond material containing Ns0concentration of greater than about 0.5 hours/million and with such a complete integrated absorption in the visible region from 350 nm to 750 nm, at least about 35% of the absorption is attributed to the Ns0moreover , this synthetic CVD diamond material has the above characteristic (b).

In yet another implementation of the present invention provides a synthetic CVD diamond material containing Ns0concentration of greater than about 0.5 hours/million and with such a complete integrated absorption in the visible region from 350 nm to 750 nm, at least about 35% of the absorption is attributed to the Ns0moreover , this synthetic CVD diamond material has the above characteristic (s).

In yet another implementation of the present invention provides a synthetic CVD diamond material containing Ns0concentration of greater than about 0.5 hours/million and with such a complete integrated absorption in the visible region from 350 nm to 750 nm, at least about 35% of the absorption is attributed to the Ns0moreover , this synthetic CVD diamond material has the above characteristics (a) and (b).

In yet another implementation of this image is the shadow provides synthetic CVD diamond material, containing Ns0concentration of greater than about 0.5 hours/million and with such a complete integrated absorption in the visible region from 350 nm to 750 nm, at least about 35% of the absorption is attributed to the Ns0moreover , this synthetic CVD diamond material has the above characteristics (a) and (C).

In yet another implementation of the present invention provides a synthetic CVD diamond material containing Ns0concentration of greater than about 0.5 hours/million and with such a complete integrated absorption in the visible region from 350 nm to 750 nm, at least about 35% of the absorption is attributed to the Ns0moreover , this synthetic CVD diamond material has the above characteristics (b) and (C).

In yet another implementation of the present invention provides a synthetic CVD diamond material containing Ns0concentration of greater than about 0.5 hours/million and with such a complete integrated absorption in the visible region from 350 nm to 750 nm, at least about 35% of the absorption is attributed to the Ns0moreover , this synthetic CVD diamond material has the above characteristics (a), (b) and (C).

The present invention is described now, just to illustrate, with reference to the accompanying drawings, in which:

Fig. 1 shows Troy the second chart, space C-H-O;

Fig. 2 shows a comparison of the spectrum of the optical absorption in the UV/visible region obtained from sample 1, layer 2 of example 1, with the spectrum obtained from VDT synthetic monocrystalline diamond type Ib;

Fig. 3 shows the spectrum of the optical absorption in the UV/visible region obtained from sample 1, layer 2 of example 1, is decomposed into its components;

Fig. 4 shows the spectrum of the optical absorption in the UV/visible region obtained from sample 2, layer 1 and sample 2, layer 2 of example 2;

Fig. 5 shows the spectrum of the optical absorption in the UV/visible region "sample 2, layer 2 of example 2, is decomposed into its components;

Fig. 6 shows the spectrum of the photoluminescence (PL)obtained at 77 K from sample 2, layer 1 and sample 2, layer 2 of example 2 by excitation radiation having a wavelength 488,2 nm, using a 50 mW Ar-ion laser;

Fig. 7 shows the photoluminescence spectrum (PL)obtained at 77 K from sample 2, layer 1 and sample 2, layer 2 of example 2 by excitation radiation having a wavelength of 514.5 nm, using a 50 mW Ar-ion laser;

Fig. 8 shows the fluorescence image obtained from sample 3 of example 3, showing a clear difference between the sample 3, layer 1 and the sample 3, the layer 2 applied on partially resolved 737 nm fluorescence trace of the sample;

Fig. 9 shows the spectrum of the optical buddy absorption the Oia in the UV/visible region, obtained from sample 4, the layer 2 of example 4;

Fig. 10 shows the fluorescence spectra obtained from sample 5, the layer 2 and sample 6, the layer 2 of example 5, obtained by excitation radiation having a wavelength of 458 nm; and

Fig. 11 shows a projection x-ray topogram received from "sample 6" of example 5.

EXAMPLES

The following examples are intended to describe the present invention without limiting the invention, the content of these examples.

Did a few examples, using processes in which the environment synthesis partly changed during CVD synthesis of diamond, so with CO2/CH4/N2you can compare directly with CH4/Ar/N2.

EXAMPLE 1

Example 1 describes the preparation of single-crystal diamond substrates, suitable for diamond deposition material according to the invention, the deposition of the layer of diamond material using the process of synthesis of CH4/N2and the subsequent deposition of the layer of material done by the method according to the invention.

1) Substrate was prepared using the following steps:

a) monocrystalline diamond chose from a range of material (natural stone type Ia and VDT-gems type Ib) on the basis of microscopic examination and observation of double refraction to find the stone, which was essentially free of otabrazeno and defects;

b) a plate with parallel surfaces with transverse dimensions of approximately 4 mm×4 mm and a thickness of approximately 500 μm and the surface Raless than 1 nm, where all the faces were within 5° from the surface {100}, was prepared from the selected diamond, using processes including laser cutting, mechanical grinding and polishing. Used processes were previously optimized to minimize subsurface defects using the method showing a plasma etching to define the levels of defects introduced by this processing.

The substrate obtained through the above steps was measured after showing etching the defect density, which depended mainly on the quality of the material and was lower than approximately 5×103defects/mm2and usually less than about 102defects/mm2.

2) Diamond substrate was mounted on a tungsten media using high-temperature diamond solder Au-Ta. It was introduced in 896 MHz microwave plasma CVD diamond reactor.

3) the Reactor was started and was subjected to the two-stage substrate predmostovoy sequence etching, consisting of:

(a) insitu oxygen plasma etching is performed using the gas flows 40/20/3000 SMS3About2/Ar/N2if Yes is the population of about 236×10 2PA (about 180 Torr) and the temperature of the substrate is approximately 716°C for about 30 minutes.

(b) the next without interrupting the hydrogen etching, removing About2from the gas stream for about 30 minutes.

4) the First layer of CVD diamond (sample 1, layer 1) was besieged on potraviny substrate by introducing CH4in the gas stream, feeding a gas stream containing 140/20/3000 SMS3CH4/Ar/N2at a pressure of approximately 236×102PA (about 180 Torr). The gas source is additionally contained atomic proportion of nitrogen of 1.4 hours/million Temperature of the substrate was 840°C. Sample 1, layer 1 was obtained by using a process well known in the art, the type and carefully characterized and, therefore, provided insitu standard with which to compare the sample 1, layer 2. The inventors have discovered that the optical properties of the diamond material in good agreement and are played for different experiments synthesis.

5) the Second layer of sample 1, layer 2 was prepared using the following conditions: gas flows 290/250/230 SMS3for CO2/CH4/N2the relation Cf:Of:Hf0,21:0,22:0,57, the ratio of Cf:Ofof 0.95:1, pressure 184×102PA (138 Torr), nitrogen present from 18 o'clock/million equivalent atomic nitrogen, and the temperature of the substrate 830°C. as for the atomic fraction of hydrogen in the gas-IP is a full, then 0,18 was added in the form of H2and 0.39 were added from other sources than the H2. The value of Hf0,57 gives the value of Parcequal to Parc=170(Hf+0,25)=139 Torr.

The sample surface was treated sufficiently to facilitate optical characterization of diamond material.

Absorption spectra in the UV/visible region were recorded, lighting one of the polished side surfaces of the sample so that the light path was completely in the layer 1 or layer 2. The length of the path used to obtain absorption spectra, approximately corresponded to the transverse size of the layer.

Before the optical characterization of the sample was affected by the deuterium lamp (the power consumption 15 Watts) for 10 minutes at the sample of approximately 80 mm from the filament of the bulb.

The experimental absorption spectrum was obtained, as described in the main part of the text. Fig. 2 shows a comparison of the absorption spectrum in the UV/visible region of the sample 1, layer 2 with a range from VDT synthetic diamond type Ib.

The experimental absorption spectrum was then subjected to deconvolution, as already described in the description, determining the concentration of Ns0. Fig. 3 shows the measured spectrum and the component type Ib for sample 1, layer 2.

The measured spectrum of the optical absorption integrated over the interval of wavelengths visible on the Asti (i.e. from 380 nm, which is equivalent to 3,2168 eV to 750 nm, which is equivalent to 1,6527 eV), obtaining the value (S) in units of eV·cm-1. The absorption attributed to Ns0similar was determined in eV·cm-1in the same wavelength interval, receiving a value (In). Then calculate the ratio V/s and the difference-In and used for characterizing the material.

Sample 1[Ns0]
(h/m)
The integrated absorption in the visible region (S) (eV·cm-1)The integrated absorption in the visible region, attributed to Ns0(In) (eV·cm-1)The difference (C-b) (eV·cm-1)The ratio (V/C)
Layer 21,950,59890,52020,07870,87

The optical results of the analysis show that for sample 1, layer 2, the proportion of optical absorption in the range from 350 nm to 750 nm, which is caused by Ns0greater than 0.35 or 35%.

Additionally, the absorption coefficients for bands of 360 nm and 510 nm was measured from the obtained by deconvolution of the spectrum at the peaks of the corresponding floor is C.

Sample 1Absorption coefficient (cm-1)
the 360 nm band (cm-1)band 510 nm (cm-1)
Layer 20,10,2

The coordinates of the CIE L*a*b* to the optical path length of 1 mm was determined from the absorption spectrum in the manner described in the detailed description of the invention, and they are listed in the table below.

Sample 1The coordinates of the CIE L*a*b* at a thickness of 1 mmThe hue angle when the optical path length of 1 mm (C)
a*b*S*L*
Layer 2-0,12,12,185,393,6

"Sample 1, layer 2, manufactured by the method according to the invention has a hue angle for the optical path length of 1 mm over 80° in addition to at least 35% of the optical absorption of the visible spectrum, caused by Ns0.

The photoluminescence spectra (PL) for sample 1, layer 1 and sample 1, layer 2 were recorded at 77 K upon excitation with light 514.5 nm 50 mW Ar-ion laser. The intensity ratio of peaks at 637 nm and 575 nm was of 0.8 and 1.4 for layers 1 and 2 respectively.

The inventors have found that the higher the value of the ratio line FL 637 nm line FL 575 nm, the closer the spectrum of the optical absorption spectrum of the pure components of type Ib. It is believed that in diamond, containing only the centers of N and NV, the ratio NV-:NV0(i.e. the ratio of the line intensities of 637 nm and 575 nm and 637 nm:575 nm) is set mainly by the following equation:

N+NV(575 nm) → N++NV-(637 nm).

However, in the diamond material, which, as discovered, contains significant contributions from acquisitions of approximately 360 nm and 510 nm, the other(s) trap(and) conquire(u)t in this electronic transfer. Using "X" to indicate this(their) trap(EC)found that:

N+X→N++X-,

where N+can be characterized by an absorption band with a peak at the photon energy of 1332 cm-1.

This competition mechanism of electronic traps leads to a decrease of relationship intensity 637 nm:575 nm.

EXAMPLE 2

The method of example 1 was followed in the steps from 1) to 4).

The second layer of CVD diamond (sample 2, layer 2) was besieged on the first layer, p is gradually changing the input gas mixture on 375/430/290 SMS 3CO2/CH4/N2at a pressure of approximately 190×102PA (142 Torr) over a period of about 10 minutes. The gas source is additionally contained 20 hours/million atomic N. the Temperature of the substrate was 840°C. the synthesis Conditions for sample 2, layer 2 had the atomic fraction of Cf:Of:Hf0,21:0,19:0,60 and the ratio of Cf:Ofto 1.1:1. As for the atomic fraction of hydrogen in gases-sources, 0,15 was added in the form of H2and 0.45 were added from other sources than the H2. The value of Hf0,60 gives the value of Parc144,5 Torr, so the operating pressure is approximately 2.5 Torr below the Parc.

Upon completion of the growth period, the substrate was removed from the reactor and a layer of CVD diamond was removed from the substrate, the top and bottom surface and two opposite side surfaces of the layer of CVD diamond polished enough for the optical characterization of the layer. The final product was a layer of CVD diamond with a total thickness of 2.4 mm (approximately uniformly distributed between layer 1 and layer 2), with transverse dimensions of approximately 3.8 mm×3,8 mm

Before the optical characterization of the sample was affected by the deuterium lamp (the power consumption 15 Watts) for 10 minutes at the sample of approximately 80 mm from the filament of the bulb.

Absorption spectrum in the UV/visible region were recorded, lighting one of polywoven the x side surfaces of the sample because of the way the light was fully on layer 1 or layer 2. Thus, the path length is used to obtain absorption spectra, approximately corresponded to the transverse size of the layer.

The spectra of optical absorption for sample 2, layer 1 and sample 2, layer 2 shown in Fig. 4. The spectrum for sample 2, layer 2 was analyzed as follows.

Component type Ib restored by deconvolution of the measured spectrum (Fig. 5).

The measured spectrum of the optical absorption integrated over the interval of wavelengths of the visible area (i.e. from 380 nm, which is equivalent to 3,2168 eV to 750 nm, which is equivalent to 1,6527 eV), receiving the value in units of eV·cm-1(C). The absorption attributed to Ns0similar was determined in eV·cm-1in the same wavelength interval (In). Then calculate the ratio V/s and the difference-In and used for characterizing the material. The values for sample 2, layer 2 are given below.

Sample 2[Ns0]
(h/m)
The integrated absorption in the visible region (S) (eV·cm-1)The integrated absorption in the visible region, attributed to Ns0(In) (eV·cm-1)The difference (C-b) (eV·cm-1) The ratio (V/C)
Layer 21,250,7370,33340,40370,45

For sample 2, layer 2" share acquisitions in the range from 350 nm to 750 nm due to Ns0is 0.45 or 45%.

Additionally, the absorption coefficients for bands of 360 nm and 510 nm was determined by means of further deconvolution of the spectrum, as described elsewhere in the description.

Sample 2Absorption coefficient (cm-1)
the 360 nm band (cm-1)band 510 nm (cm-1)
Layer 20,30,3

The coordinates of the CIE L*a*b* were determined from the absorption spectrum in the manner described in the detailed description of the invention. The values shown in the table below represent the values calculated from these values for the optical path length of 1.0 mm

Sample 1The coordinates of the CIE L*a*b*The angle of the hue when the Opti is askeu the path length 1 mm, degrees
a*b*S*L*
Layer 20,42,12,086,281,2

The fluorescence spectra for sample 2, layer 1 and sample 2, layer 2, recorded at 77 K using light 488,2 nm 50 mW Ar-ion laser, shown in Fig. 6. Spectra were normalized by the normalization of the integrated area under the Raman line of the first order when 521,9 nm in Fig. 6. Fluorescence spectrum of sample 1, layer 2 shows a peak at 543,1 nm, which is absent in the sample 1, layer 1, and is associated with a large amount of oxygen in the synthesis process.

The fluorescence spectra recorded at 77 K using a 514.5 nm light from a 50 mW Ar-ion laser from sample 2, layer 1 and sample 2, layer 2 shown in Fig. 7. The ratio peaks at 637 nm and 575 nm was 0.7 for sample 2, layer 1 and 1.1 for sample 2, layer 2. A higher value of this ratio for sample 1, layer 2 compared to sample 2, layer 1 indicates that the sample 2, layer 2 has a higher concentration of Ns0in the material.

EXAMPLE 3

Sample 3 was prepared using the same sequence of steps described in example 1, and is opened in that used the following criteria for stage 5, forming a "sample 3, layer 2: gas flows 501/604/500 SMS3for CO2/CH4/N2the relation Cf:Of:Hf0,20:0,18:0,62, the ratio of Cf:Of1,11:1, pressure of 190×102PA (about 143 Torr), nitrogen as 15 hours/million equivalent atomic nitrogen, and the temperature of the substrate 860°C. as for the atomic fraction of hydrogen of 0.62, 0,18 was added in the form of H2and 0.44 added in other species (in this case, as CH4). The value of Hf0,62 gives the value of Parc148 Torr, so the working pressure is 5 Torr less than Parc.

For this sample, the number of silicon embedded in each layer, characterized by using the fluorescence intensity of the line 737 nm, which is considered associated with a defect of the silicon-vacancy. Fig. 8 shows the fluorescence image (excited 633 nm radiation from a he-Ne laser) cross-section (the substrate on the left side of the image, superimposed on a graph of intensity for the line 737 nm. This example demonstrates that the method according to the invention inhibits the absorption of Si in the material compared to the chemotherapies H2/CH4. The peak intensity of the line 737 nm is near the boundary between the substrate and the first layer of diamond and is usually associated with higher levels of impurities during the first stage of growth of diamond, for example, due to the influence of the sources of silicon in the growth medium.

Analysis of the fluorescence spectra obtained at 77 K using a 514.5 nm light from a 50 mW Ar-ion laser for sample 3, layer 1 and sample 3, layer 2, gave the relationship of the intensities of the peaks at 637 nm and 575 nm of 0.5 and 1.1, respectively.

EXAMPLE 4

This comparative example demonstrates the effect that has on the process of synthesis of the fact that some of the hydrogen atoms is provided not in the form of molecules N2.

The procedure set forth in example 1 was repeated with the following change conditions for stage 5, forming a "sample 4, layer 2: the synthesis conditions of the growth process in the plasma on the basis of CO2/CH4without interruption by a gradual change in the composition of the gas and the working window (pressure and power). Final pressure (limited by issues of control because of the absence of added N2) set at 130×102PA (approximately 97 Torr) with respect to Cf:Of1,07:1 and the relationship Cf:Of:Hf0,246:0,229:0,525. Gas flows were 375/430 SMS3CO2/CH4. The gas source is additionally contained 20 hours/million atomic N. the Temperature of the substrate was 810°C. the Proportion of Hfthat was added in the form of molecules N2was equal to zero. As regards the share of Hfin gas-source for the synthesis of sample 4, layer 2, then the expected value of Parc132 Torr; this is significantly higher than the operating pressure of approximately 97 Torr, and developed and considered, it happens due to the lack of N added in the form of H2in a mixture of gases-sources.

Range of optical absorption in the UV/visible region for sample 4, the layer 2 shown in Fig. 9. In contrast to the previous examples, grown at higher pressures, made possible by the addition of hydrogen in the form of H2in a mixture of gases-sources range from sample 4, layer 2 shows a significant absorption in addition to a component of type Ib.

The optical properties of the sample 4, the layer 2 found by deconvolution, as described above, to determine the concentration of Ns0. The hue angle was measured and converted to the hue angle when the optical path length of 1 mm.

Sample 4The coordinates of the CIE L*a*b* at 1 mmThe hue angle when the optical path length of 1 mm (C)
a*b*S*L*
Layer 21,74,85,081,370,5

Sample 4[Ns0]
(h/m)
The integrated absorption in the visible region (S) (eV·cm-1)The integrated absorption in the visible region, attributed to Ns0(In) (eV·cm-1)The difference (C-b) (eV·cm-1)The ratio (V/C)
Layer 22,85,3140,754,5640,14

The ratio V/s 0,14 means that the ratio of optical absorption in the visible region, which is caused by Ns0is only about 0.14 or 14%, much less than for samples prepared by the method according to the invention, demonstrating the importance of H2and the desirability of operating at high pressures.

The ratio peaks at 637 nm and 575 nm is 0.7 for sample 4, layer 1 and 1.0 for sample 4, the layer 2.

Additionally, the absorption coefficients for bands of 360 nm and 510 nm was determined by means of further deconvolution of the measured spectrum, as described elsewhere in this description.

Sample 4Absorption coefficient (cm-1)
the 360 nm band (cm-1)band 510 nm (cm-1)
Layer 23,21,5

EXAMPLE 5

This example demonstrates that, provided that the atomic fraction Of C and N in Gaza-the same source, the optical properties of the obtained diamond material will be essentially the same.

The methodology used in the steps from 1) to 3) of example 1 was repeated, getting two additional sample marked "sample 5, the layer 2 and sample 6, layer 2". The original compositions of gases for sample 5, the layer 2 and sample 6, the layer 2 are summarized in the table below (the gas flows in the SMS3). The table also shows the proportion of C, N and O in the gas phase.

SampleThread SMS3The ratio of the atomic percentage
CO2COH2CH4OnlyNAbout
sample 5, the layer 25000 50059015900,200,620,18
sample 6, the layer 206149027515910,200,620,18

The source gases were chosen to obtain the same atomic fraction of C, N and O in the plasma. The ratio of Cf:Hfis 1.11:1. For both samples received thick single crystal diamond body (3.7 mm for sample 5 and 3.6 mm for sample 6), grown at a gas pressure of 170×102PA (about 127 Torr) gas source, containing 14 PM/million equivalent of atomic nitrogen. In this case Parcfor Hf=0,62 is 148 Torr.

After completion of the synthesis of the sample 5 and sample 6 was treated so that they can be optically characterize. Received the absorption spectra in the UV/visible region. The spectrum of optical absorption were subjected to deconvolution, as described elsewhere in this description, determining the concentration of Ns0. The absorption coefficients for bands of 360 nm and 510 nm was measured at the peaks of the respective bands. Key parameters are given in table the prices below.

SampleNs0
(h/m)
The 360 nm band (cm-1)Band 510 nm (cm-1)
Sample 51,50,50,45
Sample 61,20,40,35

Deconvolution coefficients and the absorption spectrum of the optical absorption shows that different gas mixtures give essentially the same result from the point of view of absorption due to each component.

The fluorescence spectra were obtained from a sample 5 and sample 6 using 514.5 nm excitation from an Ar-ion laser. The ratio peaks at 637 nm and 575 nm was 0,94 for sample 5 and 0.84 for sample 6.

The fluorescence spectra obtained from the sample 5, the layer 2 and sample 6, the layer 2 with the use of 459 nm excitation, shown in Fig. 10. And characteristics, and relative intensities of spectral features are very similar; similar results were found in other studied wavelengths of fluorescence excitation (325 nm, 488 nm, 515 nm and 660 nm).

Projection x-ray topograph of sample 6 shown in Fig. 11. There is a weak x-ray contrast, anywaysi high crystalline quality and low dislocation density. This property of the material makes this material suitable for some optical and mechanical applications.

EXAMPLE 6

This example shows the variation of the CIELAB parameters as a function of optical path length. These results obtained from the model described and mentioned in the description.

In this case the sample was obtained according to example 1, layer 2, and the absorption spectrum required to calculate the coordinates of CIE L*a*b*, were obtained from a sample thickness of 1.37 mm

Thickness (mm)0,511,52345610
L*86,485,384,3of 83.481,479,577,675,868,8
a*-0,1-0,1-0,2-0,2-0,3-0,3 -0,2-0,20,4
b*1,12,13,24,26,17,99,611,216,6
c*1,12,13,24,26,17,99,611,216,6
The hue angle, °93,993,6for 93.4br93.192,591,991,490,8and 88.8

You can see that, in particular, the hue angle is more than 80° for all thicknesses, where it was calculated.

1. Synthetic CVD diamond material containing single substitutional nitrogen(Ns0)to concentrate the radio more than about 0.5 ppm and having a fully integrated absorption in the visible region from 350 nm to 750 nm, that at least about 35% of the absorption is attributed to theNs0.

2. Synthetic CVD diamond material according to item 1, having a hue angle of more than approximately 80° to the length of the path bandwidth 1 mm.

3. Synthetic CVD diamond material according to item 1, in which the material has a photoluminescence spectrum at 77 K using 488 nm excitation from an argon ion laser, which shows a peak at from about 543,0 nm to about 543,2 nm, with the ratio of the intensity of this peak, normalized to the Raman line diamond 1-th order (if 521,9 nm for the wavelength of excitation), more roughly 0.005.

4. Synthetic CVD diamond material according to item 1, and the concentration ofNs0is more than about 2.5 ppm, measured using the peak at 270 nm using absorption spectroscopy in the UV-visible region.

5. Synthetic CVD diamond material according to item 1, the elemental concentration of individual chemical impurities other than nitrogen and hydrogen, is less than 0.1 h/million

6. Synthetic CVD diamond material according to item 1, at least about 50% of the volume of synthetic CVD diamond material is formed and the single-sector growth.

7. Synthetic CVD diamond material according to item 1, having the color parameters a* between - 20 and 1; b* between 5 and 20; C* between 0 and 30 and L* between 40 and 100.

8. Synthetic CVD diamond material according to item 1, the synthetic CVD diamond material exists as an independent object, having a thickness of more than approximately 0.2 mm

9. Synthetic CVD diamond material according to item 1, the synthetic CVD diamond material exists in the form of a layer having a thickness of about 0.5 mm or less.

10. Synthetic CVD diamond material according to item 1, with this synthetic CVD diamond material exists in the form of a doublet.

11. Gemstone containing synthetic CVD diamond material according to any one of items 1-10.

12. An electronic device containing synthetic CVD diamond material according to any one of items 1-9.

13. The method of chemical deposition from the vapor or gas phase (CVD) for synthesizing synthetic CVD diamond material according to item 1 on the substrate in the environment of the synthesis containing:
providing the substrate;
providing a gas source;
the dissociation of the gas source; and
providing opportunities homoepitaxial synthesis of diamond on the substrate;
in this environment synthesis contains nitrogen in an atomic concentration from about 0.4 ppm to about 50 ppm; and
when the gas source contains:
a) nuclear share is odorata, Hffrom about 0.40 to about 0.75;
b) the atomic percentage of carbon, Cffrom about 0.15 to about 0,30;
c) atomic ratio of oxygen Offrom about 0.13 to about 0,40;
when Hf+Cf+Of=1;
the ratio of the atomic fraction of carbon atomic fraction of oxygen, Cf:Ofcorresponds to a value approximately equal to 0.45:1<Cf:Of< approximately 1.25:1;
when the gas source contains hydrogen atoms are added in the form of hydrogen molecules H2when the atomic fraction of the total numbers of atoms of hydrogen, oxygen, and carbon between the 0.05 and 0.40; and
when this atomic fraction of HfCfand Ofrepresent the proportion of the total number of atoms of hydrogen, oxygen and carbon present in the gas source.

14. The method according to item 13, the process is carried out at a pressure Plowerexpressed in Topp, where Plower=Parc-Y, and Parc=170(Hf+0,25)+X, where Y=50 Topp, and X is from about 20 to about -50 and Parcrepresents the pressure at the beginning of the formation of unipolar arc in the process.

15. The method according to item 13, the dissociation of the gas source is performed by the microwaves.

16. The method according to item 15, the frequency of the microwaves is from about 800 MHz to about 1000 MHz.

17. The method according to item 13, the substrate support at a temperature of from primer the 750°C to about 1000°C.



 

Same patents:

FIELD: metallurgy.

SUBSTANCE: monocrystalline diamond material that has been grown using a CVD method and has concentration of single substituent nitrogen [Ns0] of less than 5 ppm is irradiated to introduce isolated vacancies V to at least some part of the provided CVD-diamond material so that total concentration of isolated vacancies [VT] in the obtained diamond material is at least more than (a) 0.5 ppm and (b) by 50% more than concentration [Ns0] in ppm in the provided diamond material; after that, annealing of the obtained diamond material is performed so that chains of vacancies can be formed from at least some of the introduced isolated vacancies at the temperature of at least 700°C and maximum 900°C during the period of at least 2 hours; with that, irradiation and annealing stages reduce the concentration of isolated vacancies in diamond material, due to which concentration of isolated vacancies in the irradiated and annealed diamond material is <0.3 ppm.

EFFECT: diamonds obtain fancifully orange colour during such treatment.

16 cl, 3 dwg, 4 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to diamond grinding in making diamond rock cutting tool. Proposed method comprises processing the diamonds in velocity layer of magnetic fields together with ferromagnetic particles. Mix composed of ferromagnetic particles and diamond grains fills the cylindrical case by 0.25-0.35 of its volume. Diamond magnetic susceptibility is defined by the relationship: X1gR1(R1+R2)224μ0ρ2R22H2X2, where X1, X2 are diamond and ferromagnetic particle magnetic susceptibility, m3/kg; g is acceleration of gravity, m/s2; R1, R2 are diamond and ferromagnetic particle grain radii, m; µ0 is magnetic permeability of vacuum, (µ0=4π·107 GN/m); ρ2 is ferromagnetic particle density, kg/m3; H is magnetic field intensity, A/m. Note here that the relationship between diamond grain weight and that of ferromagnetic particles makes 0.51-0.61.

EFFECT: higher efficiency of grinding and quality of finished diamonds.

1 cl, 2 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: method of making monocrystalline and polycrystalline diamond plates with a large surface area involves arranging, without touching each other, workpiece monocrystals with surface orientation (100) on a substrate holder, creating nucleation centres on the surface of the substrate holder free from the workpiece monocrystals, simultaneous chemical vapour deposition (CVD) of an epitaxial layer on the surface of workpiece monocrystals and a polycrystalline diamond film on the remaining surface of the substrate holder. As a result of chemical vapour deposition of the diamond, splicing of monocrystalline and polycrystalline diamond takes place on the side surface of the workpiece monocrystals to form a diamond plate of a large surface area, having spliced monocrystalline and polycrystalline diamonds. To obtain a plane-parallel CVD diamond plate, the grown composite diamond substrate is polished on both sides.

EFFECT: obtaining plates of monocrystalline and polycrystalline CVD diamond of a large surface area, having a common smooth outer surface.

5 cl, 7 dwg

FIELD: process engineering.

SUBSTANCE: invention relates to production of synthetic polycrystalline materials based on polycrystalline cubic boron containing diamond grains. Said materials are used for making cutting elements to be incorporated with drill bits, grinding wheel dressing, drilling and cutting of natural and artificial construction materials. Proposed method comprises subjecting the blend containing cubic boron nitride and diamond powder to pressure in the range of thermal stability of aforesaid components at state graphs. Note here that grain sixe of diamond powder used in amount of 5.0-37.5 vol. % makes 200-3000 mcm while that of hexagonal boron nitride makes 1-3 mcm and that of cubic boron nitride makes 1-5 mcm.

EFFECT: higher efficiency in drilling rocks of V-XII rock drillability index.

3 cl

FIELD: chemistry.

SUBSTANCE: method involves decomposition of solid carbonyl compounds of platinum metals in a gaseous medium at high temperature in a sealed container to form diamonds and doping said diamonds with boron at temperature of 150°C-500°C for 2-5 hours in a gaseous medium which contains carbon monoxide CO and diborane B2H6 with weight ratio of boron to carbon in the gaseous mixture of 1:100-1000.

EFFECT: obtaining high quality diamond monocrystals with semiconductor properties.

1 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention relates to chemical and jewellery industry. Diamonds are synthesised in a high-frequency induction crucible furnace with frequency range of 60-100 kHz. A ceramic crucible 1 is fitted with a ceramic grid 2 with holes with diameter of 0.3-0.5 mm, lying at a height of 20 mm from its bottom, and a ceramic pipe 3 with inner diameter of 15-20 mm for feeding a mixture of methane and carbon dioxide with specific volume rate of 60-70 h-1. Sodium carbonate and potassium carbonate are fed into the crucible 1, said carbonates being mixed in equimolecular ratio and heat treated at 400-450°C for 2 hours. Diamond synthesis is carried out in one day at temperature of 700-900°C in a melt of said salts in the presence of a catalyst - powdered iron with granule size of 3-5 mm in amount of 5-10% of the molten mass. Gas supply is cut at the end of the process. The molten salts, along with the catalyst and diamonds, are poured into moulds. The cooled down ingots are fed into a reactor - crystalliser 5. After dissolving the sodium carbonate and potassium carbonate, the suspension of catalyst and diamonds is fed onto a filter 6.The obtained filtrate is used in the reactor-crystalliser 5, and the diamond crystals are separated from the catalyst by a magnet.

EFFECT: invention simplifies the process, increases efficiency of the process and excludes toxic and explosive substances.

FIELD: process engineering.

SUBSTANCE: invention relates to production of diamonds and diamond polycrystalls. Proposed method comprises subjecting blend bearing carbon material and catalyst to pressure and temperature in the region of diamond thermodynamic stability. Catalyst represents a mix of metallic component with phosphorus, or the mix of alloys. Metallic component is selected from the group: iron, manganese, silicon. Metallic component-to-phosphorus ratio is selected so that to allow synthesis at temperature not exceeding 1450°C. Additionally, alloying metal may be added to said blend selected from the group: B, Si, Ti, Zr, Cr, Ni, Mo, Vo, or their mix, or alloy.

EFFECT: higher-strength and fraction resistance diamonds.

7 cl, 1 tbl, 4 ex

FIELD: process engineering.

SUBSTANCE: invention may be used in solid-state engineering in making n-type conductivity materials. Reaction system of graphite and phosphorus is sintered in hydrogen flow at 200-280°c. Then diamond is synthesized at 1450-1650°C and 6.3-7.5 GPa limited at 6.3 GPa by the range of 1550-1650°C and, at 7.5 GPa, by the range of 1450-1550°C for, at least, 40 hours. In compliance with second version, diamond is drown at seed faces {11} and {100} at 1400-1600°C and 6.3-7.5 GPa limited at 6.3 GPa by the range of 1500-1600°C and, at 7.5 GPa, by the range of 1400-1500°C at, at least, 40-60 hours.

EFFECT: efficient doping, higher quality of diamond, decreased temperature and pressure.

2 cl, 2 dwg, 1 tbl, 6 ex

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of producing a colourless monocrystalline diamond by chemical vapour deposition (CVD), which can be used in optical and jewellery applications. The method involves preparation of a substrate, using the diamond CVD synthesis atmosphere, which contains nitrogen in concentration ranging from 300 ppb to 30 ppm, and adding gas to the synthesis atmosphere, said gas containing boron in concentration ranging from 0.5 ppb to 0.2 ppm; wherein boron is added to the synthesis atmosphere in a controlled manner so as to provide stability of boron concentration higher than 20% and in an amount selected to reduce negative effect of nitrogen on the colour of the diamond, where the dominant volume of at least 80% of the monocrystalline diamond has at least one of the following characteristics: absorption spectrum, measured at room temperature, which corresponds to colour of standard circular diamond weighing 0.5 carats better than K on the Gemological Institute of America (GIA) colour scale, and absorption coefficient, measured at room temperature at wavelength 270 nm is less than 2.9 cm-1, at wavelength 350 nm - less than 1.5 cm-1, at wavelength 520 nm - less than 0.45 cm-1 and at wavelength 700 nm - less than 0.18 cm-1. That monocrystalline CVD diamond has thickness of more than 0.1 mm; nitrogen concentration in the dominant volume of the diamond ranges from 1·1014 to 5·1017 atoms/cm3, and boron concentration ranges from 3·1014 to 1·1017 atoms/cm3.

EFFECT: invention enables to obtain a colourless or almost colourless monocrystalline diamond for making gemstones and optical devices.

15 cl, 3 dwg, 6 tbl, 9 ex

FIELD: process engineering.

SUBSTANCE: invention relates to processes used in operation at high pressure and modifying substances physically. Proposed method comprises placing diamond in reaction cell in pressure transmitting medium, increasing pressure in reaction chamber and it cooling. Note here that thermal treatment is carried out at temperature increase rate of 10-50°C/s and at 2000-2350°C by passing electric current via heater in cell from programmed power supply source with due allowance for temperature relaxation in said cell in heating. For this, note also that temperature relaxation constant is defined. Said cell is cooled after heating by switching off power supply in forming short diamond heating pulse in temperature range of over 2000°C with diamond total stay time smaller than 30 seconds. Allowance for temperature relaxation in said cell in heating for heating rate Vt and pre-definition of cell temperature relaxation constant τ is made by setting in said programmable power source the maximum temperature of heating to τVT above maximum treatment temperature of 2000-2350°C.

EFFECT: changing colour of low-grate natural diamond without notable graphitisation, high-quality gem diamonds.

2 cl, 5 dwg, 3 ex

FIELD: chemistry.

SUBSTANCE: method of making monocrystalline and polycrystalline diamond plates with a large surface area involves arranging, without touching each other, workpiece monocrystals with surface orientation (100) on a substrate holder, creating nucleation centres on the surface of the substrate holder free from the workpiece monocrystals, simultaneous chemical vapour deposition (CVD) of an epitaxial layer on the surface of workpiece monocrystals and a polycrystalline diamond film on the remaining surface of the substrate holder. As a result of chemical vapour deposition of the diamond, splicing of monocrystalline and polycrystalline diamond takes place on the side surface of the workpiece monocrystals to form a diamond plate of a large surface area, having spliced monocrystalline and polycrystalline diamonds. To obtain a plane-parallel CVD diamond plate, the grown composite diamond substrate is polished on both sides.

EFFECT: obtaining plates of monocrystalline and polycrystalline CVD diamond of a large surface area, having a common smooth outer surface.

5 cl, 7 dwg

FIELD: chemistry.

SUBSTANCE: method of producing a nitride monocrystal by epitaxial growth on a base (100), having a growth plane (105), comprises steps of: forming a sacrificial layer (101) on the base (100), forming columns (102) on said sacrificial layer, growing a nitride crystal (103) layer on the columns at such growth conditions that said nitride crystal layer does not pass downwards to the base in depressions (107) formed between the columns, removing the nitride crystal layer from the base. Said columns (102) are made from material which is compatible with epitaxial growth of GaN, and the ratio D/d of the height D of one column to the distance d between two neighbouring columns is greater than or equal to 1.5.

EFFECT: invention enables to implement a method of making stand-alone GaN substrates with low density of dislocations and uniform distribution thereof.

21 cl, 37 dwg, 4 ex

FIELD: chemistry.

SUBSTANCE: composite optical material has a base in form of a transparent substrate wafer made from ZnSe, which is grown by chemical vapour deposition (CVD) whose polished surface is coated with a protective layer of ZnS, which is obtained by physical vapour deposition (PVD), wherein adhesion of the ZnSe substrate wafer to the protective layer of ZnS is provided by an optically transparent transition layer in form of a continuous row of solid solutions ZnSexS1-x, where x varies from 0 to 1, by interdiffusion of sulphur and selenium into the ZnSe and ZnS layers, respectively.

EFFECT: composite optical material ZnSe/ZnS has improved transparency in the visible and near spectral ranges, while preserving high mechanical strength of the ZnSe substrate, high adhesion of the ZnS layer to the substrate while maintaining microhardness value of the ZnS layer.

2 cl, 1 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of producing a colourless monocrystalline diamond by chemical vapour deposition (CVD), which can be used in optical and jewellery applications. The method involves preparation of a substrate, using the diamond CVD synthesis atmosphere, which contains nitrogen in concentration ranging from 300 ppb to 30 ppm, and adding gas to the synthesis atmosphere, said gas containing boron in concentration ranging from 0.5 ppb to 0.2 ppm; wherein boron is added to the synthesis atmosphere in a controlled manner so as to provide stability of boron concentration higher than 20% and in an amount selected to reduce negative effect of nitrogen on the colour of the diamond, where the dominant volume of at least 80% of the monocrystalline diamond has at least one of the following characteristics: absorption spectrum, measured at room temperature, which corresponds to colour of standard circular diamond weighing 0.5 carats better than K on the Gemological Institute of America (GIA) colour scale, and absorption coefficient, measured at room temperature at wavelength 270 nm is less than 2.9 cm-1, at wavelength 350 nm - less than 1.5 cm-1, at wavelength 520 nm - less than 0.45 cm-1 and at wavelength 700 nm - less than 0.18 cm-1. That monocrystalline CVD diamond has thickness of more than 0.1 mm; nitrogen concentration in the dominant volume of the diamond ranges from 1·1014 to 5·1017 atoms/cm3, and boron concentration ranges from 3·1014 to 1·1017 atoms/cm3.

EFFECT: invention enables to obtain a colourless or almost colourless monocrystalline diamond for making gemstones and optical devices.

15 cl, 3 dwg, 6 tbl, 9 ex

FIELD: metallurgy.

SUBSTANCE: method involves growing a diamond coating by chemical deposition of vapour in UHF plasma at a growth temperature in the deposition chamber whose atmosphere contains 5-30% of methane per unit volume of H2, on the surface of tungsten products with the axial symmetry along the axis of rotation, in the needle holders, so that the rotation body can rotate freely on its axis and move axially with the speed of radial generator displacement in the range of 10-50 mm/h.

EFFECT: improved method.

2 dwg

FIELD: machine building.

SUBSTANCE: reactor in the form of horizontal tube, which is insulated from atmosphere, includes heater, gas inlets, pumping-out pipeline with gate valve and slow pumping-out valve, and vacuum pump. In reactor there installed is substrate holder consisting of lower base 9 in the form of semi-cylinder, which contains sections 10, 11 of substrate carriers 14, which consist of two end flanges along the edges of which there fixed are strip carriers 12 with slots 13 for substrates 14; sections are fixed by means of internal end flanges; along the perimeter of end flanges and external side of strip carriers 12 there fixed is perforated casing 15; to external end flanges of lower base 9 there attached are additional flanges 17 providing coaxial location of substrate holder in the reactor; lower base 9 is closed with upper casing with perforation in the form of semi-cylinder with the radius equal to radius of lower base; casings are perforated in staggered order. Substrate holder is made of titanium sheet. Its sizes meet the following condition: L(Rp-rn)-1=2, where L -distance between substrates, Rp - inner radius of lower and upper casings; rn - substrate radius. Under substrate holder there can be installed at least one perforated tube throughout the length equal to reactor deposition zone.

EFFECT: reducing non-homogeneity of thickness of deposited layer, increasing service life of the device, simplifying its manufacturing technology, reducing the cost of obtaining dielectric semi-conductor and metal layers for production of integrated microcircuits.

4 cl, 5 dwg, 3 ex

FIELD: metallurgy.

SUBSTANCE: procedure is performed in reactor and consists in hydrogen reduction of mixture of chlorine-silane with thermal decomposition of silane, in sedimentation to required thickness of layer of poly-crystal silicon on core base heated to 1100-1200°C. Also, poly-crystal silicon is settled first on the silicon core for obtaining a layer of thickness about 2 mm. Further, surface of this layer is polarised by application of positive potential 8-10 V to it relative to the base and a loose layer of polycrystalline silicon of 1.5-2.0 mm thickness is settled, where upon polarisation potential is switched off and sedimentation of polycrystalline silicon is proceeded for obtaining a layer of required thickness.

EFFECT: simplified process of removal of layer of polycrystalline silicon settled on core base.

1 dwg

FIELD: chemistry.

SUBSTANCE: method involves preparation of a substrate, using a HOPF-synthesis atmosphere which contains nitrogen in concentration of over 300 parts per billion (ppb), and adding to the synthesis atmosphere a second gas which contains silicon atoms as dopant atoms of a second type, where dopant atoms of the second type are added in a controlled manner in an amount which ensures reduction of negative effect of nitrogen on colour, where the layer of monocrystalline diamond has thickness of greater than 0.1 mm, concentration of silicon in the dominant volume of the diamond layer is less than or equal to 2·1018 atoms/cm3, concentration of nitrogen in the dominant volume of the diamond layer is greater than 2·1016 atoms/cm3 and less than or equal to 2·1017 atoms/cm3, and the ratio of concentration of nitrogen to concentration of silicon in the dominant volume of the diamond layer is between 1:20 and 20:1. Addition of a source gas which contains silicon counters the negative effect of nitrogen contained in the HOPF-synthesis atmosphere on the colour of the diamond.

EFFECT: obtaining high-purity colourless diamond with low optical absorption.

12 cl, 6 tbl, 9 ex, 3 dwg

FIELD: machine building.

SUBSTANCE: procedure consists in injection of gas source of nitrogen and gas source of gallium into reactor for growth of layer of gallium nitride. Also, injection of gas- the source of nitrogen and gas - the source of gallium includes injection of gas containing atoms of indium at temperature from 850 to 1000°C so, that vacant centre of surface defining a cavity formed on a grown layer of gallium nitride is united with atoms of gallium or atoms of indium for filling the cavity. Internal pressure in the reactor is from 200 to 500 mbar.

EFFECT: improved surface morphology of gallium nitride layer due to reduced amount of cavities formed on it surface; device possesses improved working characteristics.

12 cl, 12 dwg

FIELD: electrical engineering.

SUBSTANCE: invention relates to production of hetero-epitaxial structures of silicon carbide on silicon that can be used as substrates in making solid-state components to be operated at high radiation and temperature. Reactor for synthesis of hetero-epitaxial silicon carbide films on silicon substrate via gas plating comprises quartz tube with container 5 accommodating substrate 1, heaters 6 with resistance or induction heating and appliances to feed film components and hydrogen into synthesis zone. Note here that hydrogen feed appliance includes active hydrogen and represents tube 9 arranged in top and bottom walls of container 5 and having holes directed along normal line to substrate 1. Note also that film component feed device is arranged in evaporator 10 with gas control ring with holes through which said components are fed into synthesis zone parallel with substrate. Mind that said feed appliances are isolated. Peculiarity of said reactor consists in that heaters and substrates are arranged parallel each other to make sandwich. Proposed design allows efficient use of radiation from every heater. Silicon carbide film synthesis is performed at pressure varying from 5·102 to 5·10-2 Pa on the surface of at least two silicon substrates at 800 to 1380°C, and hydrogen temperature exceeding that of substrate and film components by at least 100°C.

EFFECT: synthesis of high-quality hetero-epitaxial mono-crystal silicon carbide films on silicon.

5 cl, 5 ex, 3 dwg

FIELD: chemistry.

SUBSTANCE: method of making monocrystalline and polycrystalline diamond plates with a large surface area involves arranging, without touching each other, workpiece monocrystals with surface orientation (100) on a substrate holder, creating nucleation centres on the surface of the substrate holder free from the workpiece monocrystals, simultaneous chemical vapour deposition (CVD) of an epitaxial layer on the surface of workpiece monocrystals and a polycrystalline diamond film on the remaining surface of the substrate holder. As a result of chemical vapour deposition of the diamond, splicing of monocrystalline and polycrystalline diamond takes place on the side surface of the workpiece monocrystals to form a diamond plate of a large surface area, having spliced monocrystalline and polycrystalline diamonds. To obtain a plane-parallel CVD diamond plate, the grown composite diamond substrate is polished on both sides.

EFFECT: obtaining plates of monocrystalline and polycrystalline CVD diamond of a large surface area, having a common smooth outer surface.

5 cl, 7 dwg

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