Boron-alloyed diamond

FIELD: carbon materials.

SUBSTANCE: invention relates to preparation of boron-alloyed monocrystalline diamond layers via gas phase chemical precipitation, which can be used in electronics and as jewelry stone. The subject matter is uniformity of summary boron concentration in above-mentioned layer. The latter is formed in one growth sector and characterized by thickness above 100 μm and/or volume exceeding 1 mm3. Boron-alloyed monocrystalline diamond preparation involves diamond substrate provision step, said substrate having surface containing substantially no crystal lattice defects, initial boron source-containing gas preparation step, initial gas decomposition step, and the step comprising homoepitaxial growth of diamond on indicated surface containing substantially no crystal lattice defects.

EFFECT: enabled preparation of thick high-purity monocrystalline diamond layers exhibiting uniform and useful electronic properties.

44 cl, 5 tbl, 7 ex

 

The present invention relates to alloyed diamonds and, more specifically, to a layer of single-crystal diamond (hereinafter called "the diamond layer), doped with boron and obtained by the method of chemical deposition from the gas phase (HALL), and it contains diamond material or element, and method for producing a monocrystalline layer of diamond doped with boron.

There are many applications of diamond, in which it would be preferable to use a doped diamond layer of a significant size with a constant concentration of alloying elements and the resulting electronic and/or optical properties. Depending on the specific field of use of this material should essentially contain no undesirable influence on the electronic properties of impurities or defects or optically active impurities or defects. To date, the materials with such properties were not available.

For this application, as the use of power electronic equipment required solid diamond, having a thickness of from 50 to 1000 μm and lateral dimensions from 1×1 mm2up to 50×50 mm2. For production in the conditions of competition in the market is beneficial if a diamond is used in this manner, is grown in the form of a monolithic material and then treated, receiving PR the target components. In addition, when using large workpieces, it may be used for making plates of a given size, which further reduces the cost of production equipment. For optical applications, such as filters and devices for measuring the absorbed power, the large size and the considerable thickness of the raw material can be essential requirements in the manufacture of the device. Thus, the synthesis of such layers can be very profitable.

Boron is the only known alloying additive to that of diamond, which has a well documented and fairly mild effect on the diamond. Other possible alloying additives that provide a very strong influence on the study which was reported in the literature, include S, P, O, Li, but these additives are not yet not yet proven to be reliable alloying additives introduced into the entire volume of the diamond. In electronics there are many areas, for use where it is necessary doped diamond, often relatively large in size and very homogeneous properties. However, the introduction of boron in the synthesis of very strong impact on a particular sector growth. Polycrystalline diamond contains a random set of sectors, and, although the average concentration of boron for volume, larger than the size of the grain may be uniform, PR is the consideration of such amount, how much grain the local concentration of boron in it varies considerably from point to point.

Alloying additives can be introduced into the diamond through processing, carried out after completion of the cultivation. Currently, the only reliable processing after completion of the cultivation, applied to diamond, is the implantation of ions, and on the basis of the developed method of obtaining layered diamond structures, however, this method does not allow for uniform introduction of alloying elements throughout the volume. For example, the structure of type "'p-i'" (R-type - internal) can be obtained by using the implantation of boron in suitable doses and energy in high-quality natural diamond type IIa. Unfortunately, in the conditions of ion implantation are formed residual damage (vacancies and implementation). This damage cannot be completely eliminated, although processing using annealing can be reduced. Damage lead to a deterioration of the properties of charge carriers resulting from scattering on defects and compensation of boron acceptors.

Methods of deposition or growth of materials such as diamond on a substrate by chemical vapor deposition from the gas phase (method HALL) is now well established and is described in detail in the patent and other literature. In the case when ALM is C precipitated on the substrate through HALL, the method typically includes receiving a gas mixture from which the result of decomposition is obtained hydrogen or halogen (such as F, Cl) in atomic form and or carbon-containing radicals and other reactive particles, such as CHx, CFxin which x may be equal to from 1 to 4. In addition to this can be a source of oxygen, as well as sources of nitrogen or boron. When carrying out the many ways also use inert gases such as helium, neon or argon. Thus, a typical source gas mixture will contain hydrocarbons WithxHywhere each of the values x and y may be equal to from 1 to 10, or kalogeropoulou CxHyHalzin which each of the values x and z may be equal to from 1 to 10, and y can range from 0 to 10, and optionally one or more of the following gases: COxwhere x may be equal to from 0.5 to 2, O2N2and inert gas. Each gas may be present in natural isotopic ratio, or the ratio of isotopes can be artificially maintained; for example, hydrogen may be present as deuterium or tritium, and carbon may be present in the form of12With or13C. Decomposition of the source gas mixture is performed using an energy source such as microwaves, waves, radio frequency (RF), flame, term is e-cathode direct heat or electric arc, and deposition thus obtained reactive particles is conducted from the gas phase, forming a diamond.

Method HOLL diamond can be obtained on a variety of surfaces. Depending on the nature of the substrate and features of the chemistry of the process method HEGF can be obtained polycrystalline or monocrystalline diamonds.

In the deposition process a little bit easier to achieve implementation in the solid boron than implementing many other potential alloying elements.

For boron ratio, which is the implementation that is the ratio of the concentration of introduced boron (B) to carbon (C) in the solid ([In]/[S]:solid), compared with the specified value for the gas used for deposition of ([]/[]:gas), usually equal to approximately 1 (sector growth of {100}), although it varies depending on many factors. There are many ways in which in the synthesis method of HALL in diamond can be entered Bor. In the case of the use of methods with the plasma obtained with the use of microwaves, a thermionic emission cathode of the direct heat of the electric arc, the gas flow can be added DIBORANE (2H6) or another suitable gas, the source gases may be barbotirovany through methanol or acetone containing boron oxide (2About3), Orasac boron can be placed in the camera, or rod of boron can be placed in the plasma. When grown using the method of burning in the flame in the gas flow through the nozzle can be added fine mixture of methanol and boric acid. Also unintentionally lagerbuchse diamond film in the case where, for example, plasma decomposes the substrate holder, made of hexagonal boron nitride.

In the plasma synthesis can also be put nitrogen in various forms. Usually they represent the N2, NH3, air and N2H4.

Although single-crystal diamond of high purity obtained by the method of HALL is important for high-performance electronics, the number of possible applications can greatly increase if it will be possible to obtain a method of HALL doped diamond with homogeneous and useful electronic properties. In addition, there are other uses of diamond doped with boron, which are useful uniformity of color, luminescence and other properties associated with boron doping.

The invention

In accordance with the first aspect of the present invention presents a single crystal diamond layer doped with boron and obtained by the method of HALL, in the specified layer of the total boron concentration is homogeneous (without a significant change in the response by volume - the thickness of the layer) and changes in the bulk layer is not more than 50% and preferably not more than 20% when measured with the transverse resolution (resolution plane) at each measurement point is less than 50 μm and preferably, with a linear resolution of each measurement point is less than 30 μm,

and having at least one of the following characteristics:

(i) the layer formed of a single sector growth, which preferably is one of the sectors{100}, {113}, {111} and {110}, and more preferably sector {100},

(ii) the specified layer thickness exceeds 100 μm, and preferably more than 500 μm, and

(iii) the amount of the specified layer exceeds 1 mm, preferably greater than 3 mm, more preferably greater than 10 mm and even more preferably greater than 30 mm

The term "main volume", which is used in the present description and the claims, means at least 70%, preferably more than 85% and more preferably more than 95% of the total volume of the diamond layer.

Monocrystalline diamond layer doped with boron and obtained by the method of HALL according to the present invention may also contain nitrogen as alloying additives. Typically the diamond layer contains nitrogen at a concentration of not more than 1/5 of the concentration of boron and preferably less than 1 / 50th of boron concentration.

Suppose the equipment diamond layer has high quality crystallinity". In this context, the term "high quality crystallinity" allows for the presence of the alloying atoms of boron and nitrogen and associated point defects such as vacancies, the presence of hydrogen and similar defects.

Monocrystalline diamond layer doped with boron, may also be characterized by one or more of the following intrinsic properties of the primary volume where the term "main volume" defined above:

(a) layer contains uncompensated boron in a concentration of more than 1×1014atom/cm3and less than 1×1020atom/cm3, preferably in a concentration of more than 1×1015atom/cm3and less than 2×1019atom/cm3and more preferably uncompensated boron in a concentration of more than 5×1015atom/cm3and less than 2×1018atom/cm3,

(b) hole mobility (μh), measured at 300 K greater than

μh=G×2,1×1010/(Nh0,52)

for those values of Nhthat do not exceed 8×1015atom/cm3

(Equation (1))

μh=G×1×1018/Nh

for those values of Nhwith more than 8×1015atom/cm3

(Equation (2))

where Nhrepresents the concentration of holes (or, equivalently, the concentration of ionized AK is atarov boron), a functional relationship between μhand Nhbased on modern models, and the value of G represents the increase compared with the best values μhreported in recent years. The value of G is set to more than 1.1, preferably a value of more than 1.4, preferably a value of more than 1.7, and even more preferably a value of more than 2.0.

(C) Low luminescence or no signs of luminescence at 575 and 637 nm, which is associated with the presence of centres of vacancies nitrogen (N-V). More specifically, the ratio of integrated intensities of the zero phonon lines at 575 nm and 637 nm, associated with the presence of centres of nitrogen vacancies, the integrated line intensity of Raman scattering in the diamond at 1332 cm-1is less than 1/50, preferably less than 1/100, and more preferably less than 1/300, measurements at excitation argon ion laser with a wavelength of 514 nm at 77 K.

(g) the line Width of the Raman scattering measured at 300 K is less than 4 cm-1full-width of the curve at the level of half-maximum (FWHW). full width at half maximum height) is preferably less than 3 cm-1and more preferably less than 2.5 cm-1when the excitation of the argon ion laser with a wavelength of 514 nm.

(d) a High degree of homogeneity of concentration is not openserving boron based on measurements by the method of IR-spectroscopy with Fourier transform (FTIR) using techniques described below. More specifically, the probability density function of the values of the concentration of uncompensated boron defined by IR spectroscopy the FTIR method, for a representative sample, obtained from the specified layer should be such that 90% of the measurements differ by less than 50% and preferably less than 30% when calculated in percent of the mean value.

(g) Uniform emission related exciton (BE -). bound exciton) at 238 nm is in accordance with the concentration of uncompensated replacement of the boron atoms in the solid substance in the measurement BE at 77 K under UV excitation using the method described below. More specifically, the probability density function values BE measured in this way for any representative of the surface layer or of the sample obtained from the specified layer should be such that 90% of the measurements differ by less than 50% and preferably less than 30% when calculated in percent of the mean value.

(C) Significant emission intensity of free excitons (FE - from eng. free exciton), measured at 77 K under UV excitation, and emission of a homogeneous, measured by the method described below. More specifically, the probability density function of the values of FE, measured in this way for any representative of the surface layer or about what Azza, derived from the specified layer should be such that 90% of the measurements differ by less than 50% and preferably less than 30% when calculated in percent of the mean value.

High mobility, found in diamond produced by the method of HALL according to the present invention, completely unexpected. Modern change model of mobility depending on the concentration of carriers (or ionized acceptors) in the domain where the carrier concentration is more than 8×1015atom/cm3based on the assumption that the acceptors atoms of boron are of paramount importance for scattering and their contribution is essentially determined by their presence. Therefore, in accordance with this model suggest that values higher than the above cannot be achieved. In contrast, the work described in the proposal suggests that this model is wrong in the part regarding what other factors, which can be removed, previously restricted mobility doped diamond reported in the literature.

Monocrystalline diamond layer obtained by the method of HALL and doped with boron in accordance with the present invention may be a single material or to form a layer or section of a larger volume of the diamond body or with the HH. These larger diamond layer or a diamond body may be a single crystal or polycrystalline diamond obtained by the method of HALL or other method of synthesis. These diamond layer or body of a larger volume can be doped with boron, nitrogen or other elements.

The diamond layer or body according to the present invention may take the form of stone jewelry.

In accordance with another aspect of the present invention proposes a method of obtaining method HOLL monocrystalline layer of diamond doped with boron. This method includes a step of preparing a diamond substrate having a surface essentially does not contain lattice defects, the stage of preparation of the source gas and the source gas includes a source of boron, the stage of decomposition of the source gas and the stage homoepitaxial growth of diamond on the surface, essentially does not contain lattice defects, thereby obtaining a layer of single-crystal diamond doped with boron, preferably having the properties described above. In the implementation of this method is significant the fact that the growth of diamond occurs on the diamond surface, generally do not contain lattice defects.

The method according to the present izobreteny which may optionally include the use of additives nitrogen, controlled in relation to the amount of the source gas. The presence of nitrogen in the source gas allows additional control of the structure of the growing crystal, and the adoption rate for nitrogen is much lower than for boron. Such additives nitrogen, greater than 0.5 frequent. per million and less than 10,000 frequent. per million, preferably in a quantity greater than 1 hour. per million and less than 1000 frequent. per million, more preferably in a quantity greater than 3 frequent. per million and less than 200 frequent. per million per molecular nitrogen does not have a strong adverse impact on the electronic properties of doped boron layer as doped material specifically contains boron as a centre of dispersion, but does not lead to an increase in the size of the sector the growth of {100} and smaller competing growth sectors, such as {111}. This means that the growth in the plane {100} adding nitrogen can maintain the growth is almost entirely in the sector growth of {100}. Specialists in the art will appreciate stage using nitrogen, designed to change the structure, and stage of growing uniformly doped boron layer may be separate or sequential.

Thus, uniformly doped with boron diamond according to the present invention can be COI is used in a wide range of applications, in areas such as electronic detectors, electronic equipment, etc. In addition, there are other areas of use, which is useful uniformity of color, uniformity of luminescence or other properties associated with a uniform boron doping. For example, in the case of applications such as cutting edge, boron can be used for coloring of the diamond, thereby facilitating visual inspection, and uniformity of coloration can be considered as a factor indicative of the quality. Alternatively, the diamond can be used for decorative purposes, for example, in the form of a polished gemstone jewelry, for which uniformity of color is considered as one of the quality indicators.

For many applications of the invention described above, the diamond layer or material can be used in the form in which they are received, or they may be separated, for example by sawing, by obtaining two or more, usually a large number of parts or elements of smaller size, which will find application in one of the applications described above. The shape and size of parts or elements will be determined by the specific area of intended use.

Detailed description of the invention

In addition to reducing intikam, as described above, the layer of monocrystalline diamond doped with boron and obtained by the method of HALL according to the present invention can have one or more of the following characteristics for the main volume of the diamond layer, the specified principal amount identified above.

1. The amount of each individual impurity selected from the range: Si, P, S, Ni, Co, Al, Mn, Fe is less than 1 hour. per million, and the total amount of these impurities is less than 5 frequent. per million, Preferably the content of each of these impurities, other than In a and N is less than 0,05-0,5 frequent. per million, and the total content of these impurities is not more than 0.5-2 frequent. in million

2. The signal issue cathodoluminescence (CL), corresponding to the 575 nm band is weak or absent, and the peak area corresponding to the line related photoluminescence (PL)measured at 77 K and the excitation of the argon ion laser with a wavelength of 514 nm (nominal power of the incident beam 300 mW)is less than 1/50, preferably less than 1/100, and more preferably less than 1/300 of the peak area corresponding to the line Raman scattering in the diamond at 1332 cm-1.

3. According to electron paramagnetic resonance (EPR) is the concentration of neutral single substitutional nitrogen centres [N-C]° is less than 40 frequent. a billion and more t the typical less than 10 frequent. per billion.

4. According to the ESR spin density is less than 1×1017cm-3and more usually less than 5×1016cm-3when g=2,0028. In the single-crystal diamond this line at g=2,0028 associated with lattice defects and usually significant in the case of natural diamonds are type IIa diamonds obtained by the method of HALL, and diamonds, plastically deformed in the pressing, and in the case of low-quality diamonds obtained through homoepitaxial growth.

5. Excellent optical properties including transparency in the UV/visible and IR (infrared) range, close to theoretical maximum for the type IIb diamond, and, more specifically, low absorption or no absorption at a wavelength of 270 nm in the UV region (ultraviolet)associated with single substitutional nitrogen atoms, and slightly expressed or missing bands of C-H in the spectral range corresponding to the wave numbers from 2500 to 3100 cm-1(in the infrared region). Absorption spectrum of the diamond semiconductor properties, doped with boron, is characterized by continuous absorption beginning at approximately 370 MeV in the infrared part of the spectrum and continuing in the visible region up to approximately 2.2 eV. This absorption is the cause of the characteristic blue color (from light blue is about to concentrations ˜ 5×1015cm-3and to a very dark blue, up to the black, concentrations ˜5×1019cm-3). Three prominent bands at 304, 348 and 363 MeV are observed in the energy range below the threshold region of continuous absorption in the measurement at low temperature with high resolution shows up quite a lot of fine structures.

6. X-ray study of the microrelief is showing signs relating to such growth, which faces <100> source substrate grow with the formation of the faces of the <110>.

Since the concentration of potentially compensating nitrogen is significantly lower than the boron concentration, homogeneity of the distribution of uncompensated boron is usually possible to judge the total homogeneity of boron concentration.

In addition, the electronic properties depend mainly on the concentration of uncompensated boron, and not from the total boron concentration. Thus, the uniformity of the concentration of uncompensated boron is an important parameter.

The diamond containing uncompensated boron is detected characteristic feature - the one-phonon absorption with a maximum at 1282 cm-1(159 MeV). It was found that in the case of measurements at room temperature have a linear relationship between the concentration of the uncompensated borai contribution of this band in the absorption coefficient at 1282 cm -1. The concentration of boron in frequent. at 1.2 million × (absorption Coefficient at 1282 cm-1).

The diamond containing uncompensated boron, also has a characteristic absorption at 2457 cm-1(304,5 MeV), which can be detected by the subtraction own duvanova absorption. When the band at 1282 cm-1appears to be too weak to be visible, the concentration of uncompensated boron can be calculated based on the ratio of the integrated absorption band 2457 cm-1using dependencies:

the concentration of uncompensated Century (frequent. per million) = 0,00142 × the ratio of the integrated absorption at 2457 cm-1(MeV. cm-1).

Measuring the uniformity of the concentration of uncompensated boron in the entire sample volume of diamond with parallel faces can be provided through registration infrared absorption method using FTIR as follows. Build a representative map of the characteristics of the infrared absorption in the whole volume of the sample, recording the FTIR spectra at room temperature with a resolution of 0.5 cm-1and aperture 0.5 mm, the map contains at least 20 measurement points. Then, on the basis of one of the dependencies listed above, and the average value of measurement calculate the concentration of uncompensated boron in each point is. About uniformity is judged according to the schedule of the distribution of values obtained by measuring concentrations, estimating the percentage of measurements that are more distant from the mean than the permissible limit of deviation.

Range of ultraviolet cathodoluminescence (filmed at 77 K) high quality diamond doped with boron, shows strong emission related exciton Bohr when 5,22 eV (237,5 nm) and emission of free excitons at 5,27 eV (235,2 nm). For high-quality diamond with boron concentrations up to approximately 1 hour. per million, there is an approximate proportionality between the ratio of the integral intensities of these two issues, measured at 77 K, and the concentration of uncompensated boron. It is defined by dependence

[uncompensated In frequent. in million] = 1,86 × I (intensity associated excitons In) / I (intensity of free excitons).

In all the wide range of variation in the concentration of boron measurement specified ratios at different points of the sample can be used to assess the homogeneity of the characteristics of the diamond is located close to the surface points. The sample is coated with a thin (5 nm) homogeneous layer of gold in order to eliminate the accumulation of charge is fixed at 77 K using a scanning electron microscope, and use "MonoCL" for the region is ation UV spectrum cathodoluminescence (CL) at an accelerating voltage of 15 kV, the current equal to 0.2 increasing volume of computer and the size of the light spot, comprising less than 10 microns × 10 ám.

Features UV spectrum cathodoluminescence sample can be represented in a map by recording the spectra at positions defined by the intersection points (nodes) grid built using two sets of perpendicular lines, which are located with an interval of 500 μm or 1 mm, depending on the covered area, with registration data for a minimum of 30 points. Then uniformity is evaluated using density plot of the probability distribution of the measurements of concentration, determining the full width, which is a dispersion for 90% of the measurements, expressed as a percentage of the mean. This technique is used in the case of measuring the intensity of emission related excitons and emission of free excitons, for subsequent calculations of the ratio of the two intensities.

In those areas where there are significant fluctuations of defects such as "trap", which reduce the emissions associated excitons, there is an increase in fluctuations of the emissions associated excitons, if only emission related excitons is not fully repaid by the traps.

The presence of strong emission of free excitons indicates significant absence of defects such as dislocations and impurities. In amaswazi between a small number of defects and a low density of impurities and high emission of free excitons was previously described for individual crystals in polycrystalline diamond, obtained by the method of HALL. At higher boron content, usually about 20-25 frequent. per million of solid material, the emission of free excitons ultimately suppressed as a result of high density of point defects associated with the distribution of boron, and not the result of defects of crystallinity, such as dislocations. The uniformity of emission of free excitons is a good sign, confirming the absence of local areas with a high density of defects.

Analysis by the method of secondary ion mass spectroscopy (SIMS - abbr. from the English. secondary-ion mass spectroscopy) is usually carried out using a primary beam of O2+with an initial voltage of 10 kV, the beam current is typically 1 µa and a spatial resolution of less than 50 microns. The mapping is usually complete step-by-step splitting of the analyzed points with a step of 0.5 mm or 1 mm on the surface layer, with measurements for each surface is typically at least 20 points and more preferably at least 40 points. The calibration exercise compared with standard embedded boron. Obtained by the method of secondary ion mass spectroscopy data is analyzed by finding the average value for the entire data set, and then carry out the calculation, Express all results in terms of percentage of the average values for the different fractions within the range of the data is, for two opposite major surfaces of the layer, setting an approximately equal weighting in order to characterize the volume. The reproducibility of the results of secondary ion mass spectroscopy is typically of the order of 3-5%, depending on conditions, the detection limit, constituting approximately 2-5×1014atom/cm3.

In order to characterize the material throughout the volume, usually mapped results values of secondary ion mass spectroscopy (SIMS) and the ratio of BE/FE for two opposite surfaces of the material and the infrared absorption is determined by the entire thickness of the sample.

The resolution, which is inherent in methods of measurement (SEM analysis of free and bound exciton (BE, FE) and determining the concentration of uncompensated boron)that are relevant for those types of variations in the concentration of boron, which can be observed in diamond. For example, in the case of polycrystalline diamond with conventional grain size, amounting to 100 μm, when the examination with the scanning beam spot size of 1 mm in the whole volume of the sample data can be averaged out and thus could not establish a significant variation of the values of boron concentration measured for a variety of individual grains or growth sectors. Logging the data dla or more measurement points with a resolution of 50 microns or less, it is possible to show that such minor variations do not.

To obtain method HOLL homogeneous boron-doped single crystal diamond layers is important to the growing diamond was happening on the diamond substrate, essentially does not contain lattice defects. In this context defects primarily mean changes in the lattice of the crystal and cracks, but also include the boundaries of twinning, spot effects, essentially not associated with the introduced nitrogen atoms, the border with a small angle and other spatial disturbance of the crystal lattice. Preferably the substrate is a diamond with a low double refraction, natural type Ia or synthetic diamond, obtained at high pressure and high temperature, type Ib or IIa, or synthesized by the method of HALL monocrystalline diamond. Defects can lead to deterioration of material properties in two ways: negatively modify the electronic properties (for example, the hole mobility), as well as to influence the local absorption of boron. Since the increase in the number of changes in the lattice of the crystal occurs during growing thick layers, the control of such changes in the early stages of growth is particularly important.

The defect density is easiest on init optically after the implementation of plasma or chemical etching, aimed at identifying defects (referred to as plasma etching for defect detection), for example, after the implementation of the rapid plasma etching described below. Can be found two types of defects:

1) Defects, the cause of which is the quality of the substrate material. If selected as a substrate of natural diamond density of such defects is minimal can reach 50/mm2more typical values are 102/mm2although in the case of other diamonds density can be 106/mm2or more.

2) Defects caused by polishing, including structural dislocations and microcracks, contribute to the appearance of traces of vibration (sometimes referred to as tracks) along the direction of polishing. The density of such defects can vary greatly within a single sample, and typical values are between approximately 102/mm2to more than 104/mm2in a poorly polished sections or samples.

Preferred is such a low density of defects, in which the surface density of the signs that occurred after etching and is caused by defects, which are described above, is less than 5×103/mm2and more preferably less than 102/mm2.

The number of defects n the surface and under the surface, it is used for growing diamond by the method of HALL, can thus be reduced by careful preparation of the substrate. Under the training here refers to any process undertaken in relation to the material spring of origin (in the case of natural diamond or synthetic origin (in the case of synthetic diamond), because each stage can influence the defect density on the surface of the material, which in the end will turn into the surface of the substrate after the completion of training material for use as the substrate. The specific stage of processing may include the widely known methods of diamond processing, such as mechanical cutting, grinding and polishing (in this application specifically optimized for small amounts of defects), as well as less widely known methods, such as laser processing, the introduction of ions and method of removing layers, chemical/mechanical polishing and chemical treatment liquid, and plasma. In addition, the value of RQfor the surface (standard deviation of surface profile from the plane obtained by using a roughness meter with a pen, preferably a dimension along the line segment length 0.08 mm) should be minimized, typical values of this Velich the us before any plasma treatment is not more than a few nanometers, that is less than 10 nanometers.

One of the special ways to minimize damage to the surface of the substrate is plasma etched surface, which will be homoepitaxially growth of diamond is carried out in situ. Generally speaking, does not necessarily have this etching in situ or immediately before the implementation of the growth process, but the largest gain is obtained if the etching conduct in situ, because this eliminates the possibility of further physical damage or chemical contamination. Etching in situ also is usually the most convenient, as the process of cultivation also occurs in the plasma. For plasma etching, we need the same conditions to obtain a coating method, deposition, or the process of growing diamond, but in the absence of any carbon-containing source gas and, in General, somewhat lower temperature, to better adjust the speed of etching. For example, this etching may consist of one or more of the following types of etching:

(i) oxygen etching using mostly hydrogen, optionally using a small number of Ar and necessarily using a small number Of2. Typical conditions oxygen etching JW is Auda: pressure 50-450× 102PA, the use of gas for etching, containing from 1 to 4 percent oxygen, from 0 to 30 percent argon and the rest is hydrogen, all percentages refer to the volume, the temperature of the substrate 600-1100°With (more typical 800°C)the normal duration of the process is 3-60 minutes,

(ii) hydrogen etching, which is similar to etching under item(i), but which does not use oxygen,

(iii) can be used for alternative methods of etching, which are based not only on the use of argon, hydrogen and oxygen, for example, the methods with the use of Halogens, other inert gases or nitrogen.

Typically, the etching includes oxygen etching, and then the hydrogen etching, and then pass directly to the synthesis, introducing a source gas containing carbon. Duration/temperature etching is chosen in such a way as to remove the damage remaining after processing and to remove all surface contamination, but in such a way as not to cause the formation of extremely rough surface and does not etch in a significant degree of spatial defects, such as dislocations, which after such etching could pass through the entire surface and to form deep grooves. Since the etching is aggressive treatment, at this stage osobennaja thus to design the camera to process and to pick up materials for its parts, to the materials under the influence of the plasma is not passed in the gas phase or did not get on the surface of the substrate. Hydrogen etching, after oxygen etching, not so selective with respect to defects in the crystal lattice surrounding the bumps caused by oxygen etching, actively influencing such defects, and allows you to get a smoother and higher quality surface for subsequent cultivation.

The surface or the surface of the diamond substrate on which the growth of diamond produced by the method of HALL, preferably represent a surface{100}, {110}, {113} or {111}. Due to the technological complexities of the real characteristics of the surface structure of the sample may differ from these ideal characteristics on the value up to 5°and, in some cases up to 10°although this is less desirable, since it adversely affects reproducibility.

For implementing the method according to the present invention, it is also important that the content of impurities in the atmosphere, in which there is growth in terms of the way HALL, was closely monitored. More specifically, the growth of the diamond must be carried out in an atmosphere essentially not containing any impurities, and concentration specifically added (boron and nitrogen, in the case of its use is litvania) must be properly controlled. The degree to which you want to monitor the concentrations of the alloying of boron and nitrogen depends on the specific type of subsequent use, but typically should not vary by more than 20% and more typically not more than 10% and even more usually not more than 3%. Such control requires careful control over the content of nitrogen impurities in the feed gas, as nitrogen is a common impurity. To achieve this degree of control, the content of nitrogen in the feed gas to the special addition of nitrogen it generally supports equal less than 500 parts per billion in the gas phase (in the form of the molecular fraction in the total volume of gas), preferably less than 300 ppb and more preferably less than 100 parts per billion. Measurement of absolute and relative concentration of nitrogen in the gas phase at such low concentrations as 100 frequent. per billion, requires sophisticated equipment for observation, for example gas chromatography equipment. An example of how to perform such measurements will be now described.

The usual methodology for gas chromatography (GC) is as follows: a sample of the gas flow away from the point of interest using a narrow feed channel sample, optimized from the point of view of maximum flow rate and minimum is ertvye volume, and passed through the GC-spiral tube of the sample. GC-spiral tube for sample is a segment of the spiral tube fixed and known volume (usually 1 cm3for introduction at standard atmospheric pressure), which can be switched from its location in the supply line of the sample in gas-carrier (helium (Not) high purity), from which the flow in the columns for gas chromatography. This allows you to enter a gas sample of known volume in the thread that enters the column; according to the methodology of GC this operation is called "introduction of the sample.

Put the sample carried by the carrier gas passes through the first GC column (filled with molecular sieves selected to distinguish simple inorganic gases) and partially divided, but a high concentration of basic gases (e.g., N2, Ar) causes saturation of the column, making it difficult to separate, for example nitrogen. The relevant part effluent from the first column serves on the entry in the second column, thereby eliminating the supply of the majority of other gases in the second column, prevents saturation of the column and the opportunity to completely separate the target gas (N2). This operation is called "selection of the main fraction".

The stream exiting the second column, miss h is cut discharge ionization detector (GUIDE), which determine the increase of leakage currents through the carrier gas is caused by the presence of the sample. The chemical structure is determined by the standard retention time of the gas calibration is performed with the use of standard gas mixtures. The signal discharge ionization detector is linear over up to five orders of magnitude, and for calibration of the detector using a special precisely measured gas mixture, typically in the range 10-100 frequent. per million, measured gravimetrically and then checked upon delivery. Linearity can be tested in experiments carried out with exactly dilution.

This known method of gas chromatographic analysis was modified for use according to the present invention as follows. All these processes are usually carried out at a pressure of 50-500×102PA. In normal operations when carrying out gas chromatography using gaseous sample, which is at a pressure higher than atmospheric in order to conduct the gas through the supply line of the sample. In the present invention, the sample serves as an attachment to the output end of the line vacuum pump, and the sample is moved through the use of low atmospheric pressure. However, although the gas and moves, resistance from the line can cause a significant drop in line pressure, exerting an undesirable influence on the calibration and sensitivity. Therefore, between the spiral tube for the sample and a vacuum pump is placed a valve, which is closed for a short time before submission of the sample, in order to provide the ability to stabilize the pressure in the spiral tube with the sample and to measure the pressure gauge. In order to ensure the introduction of a sufficient quantity of the sample gas, the volume of the spiral tube for sample increased to approximately 5 cm3. Depending on the scheme of supply of the sample gas, this technique can be effectively used up to pressures of approximately 70×102PA. GC-calibration depends on the mass of the introduced sample, and the highest accuracy is achieved when GC is calibrated using the same pressure pattern as that in which the analyzed gas will be fed into the analysis process. In order to be sure of the correctness of measurements, one must be able to work with vacuum and gases at a very high level.

In order to analyze the incoming gases, the feed point of the sample can be positioned upstream relative to the camera of the synthesis, in order to describe the environment in the chamber of the synthesis inside the cell fusion, or the point can be located downstream p is to the camera synthesis.

Usually (boron) is added to the system in the form of In2H6using the source according to the calibration of nominally 100 frequent. per million2H6in N2to simplify control, and so enter into nitrogen in the form of N2using the source according to the calibration of nominally 100 frequent. at million N2in N2to simplify control. The amount added as boron (b), and nitrogen (N) is expressed as the frequent. per million, carrying out calculation for boron (B) in the form [V2H6]/[Gases], where [B2H6] represents the number of moles In2H6and the [Gaza] represents the number of moles of all gases, and similarly in the form [N2]/[Bce gases] for N2.

The gas mixture used in the synthesis process, can contain any gases, known from the prior art, and must contain a carbon-containing substance which will decompose with the formation of radicals or other reactive particles. The gas mixture also will usually contain gases that are suitable for hydrogen or halogen in atomic form.

The decomposition of the source gas is preferably carried out using microwave energy in the reactor, examples of possible reactors are well known in the prior art. However, you should minimize the migration of contaminants from the reactor. In order to ensure that the, that the plasma is not in contact with any surfaces except the surface of the substrate on which is grown diamond, and its mount (carrier substrate) can be used system based on microwave technology. Examples of preferred materials for the mount are molybdenum, tungsten, silicon and silicon carbide. Examples of preferred materials for the manufacture of cameras synthesis reactor are stainless steel, aluminum, copper, gold and platinum.

Use the plasma with a high density energy source which can serve microwave with high energy (usually 1-60 kW, for a media substrate with a diameter of 25-300 mm) and high pressure gas (50-500×102PA and preferably 100-450×102PA).

When using the above conditions, it was possible to obtain by the method of HALL thick high-quality single-crystal diamond layers, doped with boron, with an unusually high mobility of charge carriers with morphology, which is optimized for homogeneous large amounts suitable for commercial use.

Hereinafter will be described some examples according to the present invention.

Example 1

Substrates required for the synthesis of single-crystal diamond by the method of HALL according to the present invention, can be p is Gotovina as follows:

(i) the Choice of the base material (natural stone type Ia and VDT-gems type Ib) is carried out on the basis of studies with a microscope and analysis of double refraction to identify substrates that do not contain deformations and defects.

ii) To minimize the number beneath the surface defects using laser cutting, grinding and polishing, and a method of plasma etching for defect detection in order to detect defects introduced by the processing.

iii) After studies conducted to implement the optimal choice, it was easy to obtain substrates with defect density measured after etching for detection of defects and depends above all on the quality of the material, the density is less than 5×103/mm2and, typically, less than 102/mm2. The substrate prepared in this way is then used in the subsequent synthesis.

Synthetic diamond type 1b, obtained by high temperature/high pressure and intended for use as a substrate, is grown in the high pressure autoclave, and then use the technique described above, to minimize the defects of the substrate and then form a polished plate with dimensions 7,65×8,25 mm2and a thickness of 0.54 mm, that is, all surfaces have an index on {100}. The surface roughness RQat this stage is less than 1 nm. The substrate is fixed on tungsten media using high-temperature solid diamond solder. The item received is placed in a reactor and begin to carry out the cycles of etching and growth, as described above, namely:

1) Reactor (2.45 GHz) pre-filled cleaners, reducing the number of random impurities in the incoming gas stream to less than 80 frequent. per billion.

2) Exercise oxygen plasma etching in situ using 15/75/600 sxms (standard cubic centimeters per second) O2/Ar/N2at a pressure of 270×102PA and the temperature of the substrate 753°C for 10 minutes.

3) the etching is continuously transferred to the hydrogen etching, removing About2from the gas flow at a temperature of 758°C for 10 minutes.

4) the etching is transferred in the process of growing, adding a carbon source (in this case, - CH4and gases supplements. In this case, CH4serves at 30 sxms. As the source of the alloying additive is boron used In2H6. The concentration of B2H6in the gas phase is 1.4 frequent. per million Temperature is 780°C.

4) After the period of growth of the diamond substrate is removed from the reactor, and the diamond obtained by the method of HALL, separated from padlock is.

5) This layer is then polished, getting a uniformly doped layer 735 μm with faces <100> and transverse dimensions of approximately 5×5 mm2.

6) This layer, referred to as CD-1, cleaned and lightly calcined in oxygen to obtain a surface treatment which completes the influence of her About2and test the mobility using the methods of the Hall. Mobility is 360 cm2/Vs at 300 K and 185 cm2/Sun at 440 K.

These data are consistent with T-3/2dependence, as expected from the model of the acoustic phonon scattering.

7) the Specified layer is analyzed by means of secondary ion mass spectroscopy (SIMS), measurements indicates that the layer is characterized by a homogeneous concentration of the boron component 6,2×1018atom/cm3.

8) the carrier Concentration is measured using the methodology of Hall and determines that the concentration is 4.5×1013at 200 K, 4×1015at 300 K and 1.6×1017at 500 K. on the Basis of carrier concentration equal to 4×1015at 300 K, by equation (1) predicts the upper boundary mobility for the specified material, components 163 cm2/Sun, despite the fact that the measured value is 360 cm2/Sun. Thus, the value of the multiplier G (determined at the level of the AI 1 above), more than 2.2, indicates the improvement and advantages in comparison with the materials known from the prior art.

Example 2

Repeat the procedure described in example 1 with the following changes:

1) as substrate using polished plate VDT-diamond (obtained at high pressure and high temperature), size 5×5 mm and a thickness of 500 μm, all surfaces have an index on {100}.

2) Conduct oxygen plasma etching in situ using 15/75/600 SXM O2/Ar/H2at 333×102PA and the temperature of the substrate 800°C for 30 minutes.

3) After that for 30 minutes to carry out a hydrogen etching process in which from the reaction stream is removed O2temperature is 810°C.

4) Initiate the growth process by adding the flow of CH4at 36 SCCM, and flows In a2H6and N2in an amount such that the concentration of these gases was 0.05 and 7 frequent. at million, respectively. Temperature is 812°C.

5) Upon completion of the growth period from the reactor to clean the substrate and separated from her diamond layer obtained by the method of HALL.

6) the surface of this layer, identified as CD-2, then buff with getting this layer thickness of 410 μm from all sides of the <110> and spatial dimensions 7×7 mm2.

7) Indicated the p layer is analyzed by means of secondary ion mass spectroscopy (SIMS) and after a number of measurements set, the layer is characterized by a homogeneous concentration of the boron component 6,1×1016atom/cm3. On the map concentrations of boron, built according to SIMS, not detected changes in concentration within the map resolution, lateral resolution which is less than 30 mm, with a sensitivity to this distinction value measurements, which is less than 10%. The measured concentration of nitrogen is less than 5×1015atom/cm3.

8) This layer, referred to as CD2, clean and slightly burnt in oxygen to obtain a surface treatment which completes the influence of her About2and test the mobility and carrier concentration. The measured carrier concentration greater than 4.5×1013and the measured mobility is more than 2.5×103cm2/Sun, thus, the value of G is approximately 1.5.

9) Layer CD 2 further characterized by the following properties described below:

(i) the Range of cathodoluminescence (CL-range) indicates the presence of free and bound excitons and the lack of other features.

(ii) the Spectrum of electron paramagnetic resonance (EPR spectrum) indicates the absence of neutral substitutional nitrogen in the spectrum, there is only a line with a slight intensity at g=2,0028.

(iii) In the optical spectra of n is observed absorption, close to theoretical, in addition to the characteristic absorption associated with the presence of uncompensated boron at a concentration of 6.5×1016atom/cm3.

(iv) the map x-ray curves swing set that the angular divergence in the sample is less than 10 seconds of arc.

(v) In the spectrum of Raman scattering is observed line width (full width at half-maximum level) approximately 2 cm-1.

Example 3

Repeat the procedure described in example 1 with the following changes in growing conditions:

Ar - 75 SCCM, N2- 600 SCCM, CH4- 30 SCCM, 330×102PA, 795°C, 4.4 kW, the concentration of boron and nitrogen in the gas phase, respectively 15 and 0.5 frequent. in million

Grown by the method of HALL diamond layer is then treated in a suitable manner and analyze both surfaces of this layer, which has a thickness of 300 μm.

On the upper surface map data secondary ion mass spectroscopy (SIMS), the concentration of boron is 1.75×1019cm-3and on the opposite side of the average concentration according to SIMS is 1,98×1019cm-3.

Example 4

Repeat the procedure described in example 1 with the following changes in growing conditions:

Ar - 50 SCCM Ar, N2- 600 SCCM, CH4- 40 SCCM, 330×102PA, 795°, 4,4 kV is, the concentration of boron and nitrogen in the gas phase respectively of 0.05 and 0.7 frequent. in million

Grown by the method of HALL diamond layer is then treated in a suitable manner and analyze both surfaces of this layer, having a thickness of 113 μm.

To the upper surface of the build maps SIMS increments of 0.5 mm in 2 mm × 4.5 mm, and more plot 5 mm × 6 mm in increments of 1 mm For the bottom surface of the data register in increments of 1 mm, Thus, the analyzed volume is 3.4 mm3.

The average concentration of boron on the front surface measurements is 0.56 frequent. per million and the back surface - 0,52 frequent. in million Percentage volume of material, thus falling within the specified range of concentrations near the mean, are presented in table 1.

Table 1.

The concentration and distribution of boron according to secondary ion mass spectroscopy (SIMS) with 1 mm increments
SIMS
IndexUnitFeaturesSurfaceVolume
The average concentration of boron (frequent. per million)frequent. per milliontopbottom
step 1.0 mm0,560,520,54
The range of values%100%from -24% to +23%from -14% to +16%from -21% to +27% (range 48%)
95%from -17% to +20%from -14% to +11%from -17% to +18% (range 35%)

SIMS
IndexUnitFeaturesSurfaceVolume
The average concentration of boron (frequent. per million)frequent. per milliontopbottom
step 1.0 mm0,560,520,54
85%from -11% to +14%from -11% to +11%from -15% to +13% (range 28%)
70%from -9% to +9%from -7% to +9%from -9% to +10% (range 19%)

Thus, from the data in table 1 one can see that 100% of measuring the concentration of boron (B) fall in the total interval, constituting 47% for the upper surface of the sample, and are in the range of 30% to the rear face of the sample, and in the interval, stood the Commissioner, 48% for both of the major surfaces, the bounding volume, subjected to analysis. Similarly, 70% of these measurements fall in the range of around 19% for both surfaces together.

The measured concentration of nitrogen in the layer is less than 0,06 frequent. per million, this upper limit is determined by the sensitivity of the instruments in the measurement conditions.

The rear surface of the sample is then analyzed using SEM, using a system of "MonoCL for measuring intensities of free and bound excitons (FE and BE), the data was filmed array 6x6 (36 measurement points) in increments of 1 mm, the results are shown in table 2.

Table 2.

The scatter of measurements of free and bound excitons (FE and BE)
% dimensionsThe entire range of values (in % of average)
TopBottom
BEFEBE/FEBEFEBE/FE
100%413431
95%392928
90%251825
85%201524
70%141217

Thus, 90% of the measurements on the bottom surface of the sample fall in the interval of 25% from the average value for the free excitons, 18% from the average value for the associated excitons and 25% from the average value for the relationship BE/FE.

Example 5

Grow layer by the method described in example 4. Then the layer appropriately process and analyze the front and rear surfaces, the thickness of the layer is 233 μm. The analyzed volume is 7.0 mm

Determine the concentration of boron, which is about 0.34 frequent. on million on the upper surface, 0,29 frequent. on million on the bottom surface, and an average value of 0.32 frequent. in million Percentage amount of material that falls therefore within the specified range of concentrations near the average values presented in table 3.

Table 3.

Measurement of the distribution of boron (B) method of secondary ion mass spectroscopy (SIMS)
% volume of the layer Evaluation of deviations and ranges of measurements of the concentration of boron in percent of the mean value
Assessment bottomThe upper estimateScatter
100%-22%+24%46%
95%-21%+19%40%
85%-13%+13%26%
70%-10%+9%19%

The measured concentration of nitrogen in the layer is less than 0.03 frequent. per million, this upper limit is determined by the sensitivity of the instruments in the measurement conditions.

Then the front and back surfaces of the sample analyzed with SEM using system MonoCL for measuring intensities of FE and BE, the data was filmed array 6×6 (36 measurement points) in increments of 1 mm, the results are presented in table 4.

Table 4.

The scatter of the measurements for the free and bound excitons (FE and BE)
% dimensionsThe entire range of values (in % of average)
TopBottom
BEFEBE/FE BEFEBE/FE
100%201426192932
95%161222172421
90%131118142117
85%11917131414
70%1081411912

Using the upper and lower main surfaces of the layer as two representative surfaces, find that 90% of the measurements related to excitons and free excitons and relations BE/FE deviate from the mean value being less than 30%.

Example 6

Grow layer by the method described in example 4. Then the layer appropriately process and analyze the front and rear surfaces, the thickness of the layer is 538 μm. Analyzed the amount of $ 16.1 mm3.

Determine the concentration of boron, which is 0.52 frequent. on million on the upper surface, 0,34 frequent. on million on the bottom of the surface, and the average value is 0.43 frequent. per million According to the data obtained 70% of the volume of the specified layer fall in the interval from -23,3 to +23,4 from the average value, the total variation is to 46.7%.

Then repeat the mapping of research results in the presence of boron by means of secondary ion mass spectroscopy (SIMS) for surface growth with a resolution of less than 30 μm in order to further demonstrate the local homogeneity of the introduction of boron, the data obtained are shown below in table 5. Analysis of elements other than carbon, indicates the absence of impurities when the threshold value of detection of 0.5 frequent. in million

The measured concentration of nitrogen in the layer is less than 0.03 frequent. per million, this upper limit is determined by the sensitivity of the instruments in the measurement conditions.

Then the front and back surfaces of the sample analyzed with SEM using system MonoCL for measuring intensities of free and bound excitons (FE and BE), the data is removed in the area of 6×6 (36 measurement points) in increments of 1 mm, the results are presented in table 5.

Table 5.

The scatter of measurements of free and bound excitons (FE and BE) and the concentration of boron (B)
% dimensionsIn the camping interval values (in % of average)
TopBottom
Conc. In*1Conc. In*2BEFEBE/FEConc. In*2BEFEBE/FE
100%253041333029201325
95%242439282725161222
90%251824131018
85%15221915231611817
70%121414121799813
*1Secondary ion mass spectroscopy, the resolution of <30 μm

*2Secondary ion mass spectroscopy, the resolution of <50 microns

This layer also Carteret, exploring the infrared absorption at plot 5×5mm (36 measurement points) in increments of 1 mm, to assess the fluctuations of the content of uncompensated boron. 90% of measurements fall in the range of deviations from the mean width of 34%.

Shoot spectra Raman/photoluminescence plate at 77 K, using light of an argon ion laser with a wavelength of 514 nm. The strongest in the spectrum is the line Raman scattering in the diamond at about 1332 cm full width at the level of half-maximum (FWHW) is 1.6 cm-1. The zero phonon line at 575 nm and 637 nm are beyond the detection threshold, and the highest value for the relationship to their maximum intensities, respectively, to the intensity corresponding to the maximum Raman scattering is 1:1000.

Example 7

Grow layer by the method described in example 4. Then the specified layer process, receiving layer 818 μm, and is mapped IR absorption at plot 5×5 mm (36 measurement points) in increments of 1 mm, for measurements of fluctuations of the content of uncompensated boron. 90% of measurements fall in the range of deviations from the mean width of 13%.

1. A monocrystalline layer of diamond doped with boron and obtained by the method of chemical deposition from the gas phase (HALL), in which the total concentration of boron homogeneous and changes in the bulk layer is less than 50%, when the measurement is AI with transverse resolution, constituting less than 50 μm for each point at which conduct the measurement, and in which the main volume of the layer is at least 70% of the total volume of the layer, and the layer has at least one of the following characteristics (i)to(iii):

(i) the layer formed in a single growth sector

(ii) the thickness of the layer exceeds 100 μm, and

(iii) the volume of the layer exceeds 1 mm3.

2. A layer of single crystal diamond according to claim 1, in which the variation of characteristics in the bulk is less than 20%.

3. A layer of single crystal diamond according to claim 1 or 2, in which the variation of the characteristics measured transverse resolution for each measurement point, amounting to less than 30 microns.

4. A layer of single crystal diamond according to claim 1, in which the main volume of the layer contains uncompensated boron at a concentration above 1·1014at./cm3and less than 1·1020at./cm3.

5. A layer of single crystal diamond according to claim 1, in which the majority of the volume layer contains uncompensated boron at a concentration above 1·1015at./cm3and below 2·1019at./cm3.

6. A layer of single crystal diamond according to claim 1, in which the majority of the volume layer contains uncompensated boron in concentrations above 5·1015at./cm3and below 2·1018at./cm3.

7. Layer monokristallicheskogo the diamond according to claim 1, in which hole mobility (μh), measured at 300 K greater than

μh=G·2,1·1010/(Nh0,52)

for those values of Nhthat do not exceed 8·1015atom/cm3,

μh=G·1·1018/Nh

for those values of Nhwith more than 8·1015atom/cm3,

where Nhrepresents the concentration of holes, and G has a value of more than 1.1.

8. A layer of single crystal diamond according to claim 7, in which G has a value greater than 1,4.

9. A layer of single crystal diamond according to claim 7, in which G has a value of over 1.7.

10. A layer of single crystal diamond according to claim 7, in which G has a value greater than 2.

11. A layer of single crystal diamond according to claim 1, which is characterized by low luminescence or absence of signs of luminescence at 575 and 637 nm, associated with the presence of centres of vacancies nitrogen (N-V).

12. A layer of single crystal diamond according to claim 1, in which the ratio of each of the integrated intensities of the zero phonon lines at 575 nm and 637 nm, associated with the presence of centres of nitrogen vacancies, the integrated line intensity of Raman scattering in the diamond at 1332 cm-1is less than 1/50, when conducting the measurements at 77 K and the excitation of the argon ion laser with a wavelength of 514 nm.

13. SL is the first single-crystal diamond according to item 12, where the ratio is less than 1/100.

14. A layer of single crystal diamond according to item 12, in which the ratio is less than 1/300.

15. A layer of single crystal diamond according to claim 1, characterized by line Raman scattering width of less full width of the curve at the level of half-maximum (FWHW), component 4 cm-1when conducting measurements at 300 K and the excitation of the argon ion laser with a wavelength of 514 nm.

16. A layer of single crystal diamond according to § 15, in which the line width of the Raman scattering is less than the full width of the curve at the level of half-maximum (FWHW), component 3 cm-1.

17. A layer of single crystal diamond according to § 15, in which the line width of the Raman scattering is less than the full width of the curve at the level of half-maximum (FWHW), part 2.5 cm-1.

18. A layer of single crystal diamond according to claim 1, in which the probability density function of measured values of the amount of uncompensated boron, obtained by the method of IR-spectroscopy with Fourier transform (FTIR), for a representative sample, taken from the layer is such that 90% of the measurements deviate from the mean by less than 50%.

19. A layer of single crystal diamond according to claim 1, in which the probability density function of measured values of the amount of uncompensated boron, obtained met the house of infrared spectroscopy with Fourier transform (FTIR), for a representative sample, taken from the layer is such that 90% of the measurements deviate from the mean by less than 30%.

20. A layer of single crystal diamond according to claim 1, in which the probability density function of measured values of emission related exciton (BE) representative of the surface layer or sample taken from the layer is such that 90% of the measurements deviate from the mean by less than 50%.

21. A layer of single crystal diamond according to claim 1, in which the probability density function of measured values of emission related exciton (BE) representative of the surface layer or sample taken from the layer is such that 90% of the measurements deviate from the mean by less than 30%.

22. A layer of single crystal diamond according to claim 1, in which the probability density function of the measurement values of the emission of free excitons (FE) for the representative of the surface layer or sample taken from the layer is such that 90% of the measurements deviate from the mean by less than 50%.

23. A layer of single crystal diamond according to claim 1, in which the probability density function of the measurement values of the emission of free excitons (FE) for the representative of the surface layer or sample taken from the layer is such that 90% of the measurements deviate from the mean by less than 30%

24. A layer of single crystal diamond according to claim 1, in which the primary volume is more than 85% of the total volume of the layer.

25. A layer of single crystal diamond according to claim 1, in which the basic amount is more than 95% of the total volume of the layer.

26. A layer of single crystal diamond according to claim 1, wherein said layer is formed from a single sector growth, which is one of the sectors{100}, {113}, {111} and {110}.

27. A layer of single crystal diamond according to claim 1, which has a thickness greater than 500 μm.

28. A layer of single crystal diamond according to claim 1, which has a volume of more than 3 mm3.

29. A layer of single crystal diamond according to claim 1, which has a capacity exceeding 10 mm3.

30. A layer of single crystal diamond according to claim 1, which additionally as an alloying agent contains nitrogen.

31. A layer of single crystal diamond according to item 30, in which the nitrogen concentration does not exceed 1/5 of the concentration of boron.

32. A layer of single crystal diamond according to item 30, in which the nitrogen concentration is less than 1/50 boron concentration.

33. The diamond material in which the layer of single crystal diamond according to claim 1 is a layer or region of the specified diamond material.

34. Diamond material on p or a layer of single crystal diamond according to claim 1 in the form of stone jewelry.

35. The item received from the layer of monocrystalline Alma is rather according to claim 1 or of the diamond material p.

36. A method of obtaining a layer of single-crystal diamond doped with boron, comprising a step for diamond substrate, which has a surface essentially free from defects in the crystal lattice, the stage of obtaining the source gas that includes a source of boron, the stage of decomposition of the source gas and the stage homoepitaxial growth of diamond on a given surface, essentially does not contain lattice defects.

37. The method according to p, in which a monocrystalline layer of diamond doped with boron, has the characteristics of a layer according to any one of claims 1 to 32.

38. The method according to p, in which the source gas contains nitrogen in an amount to provide the control structure of the growing single-crystal diamond.

39. The method according to § 38, in which the amount of nitrogen added to the source gas, is more than 0.5 hours/million and less than 10000 hours/million

40. The method according to § 38, in which the amount of nitrogen added to the source gas is more than 1 h/m and less than 1000 hours/million

41. The method according to § 38, in which the amount of nitrogen added to the source gas, is more than 3 hours/million and less than 200 hours/million

42. The method according to p, in which the density of surface defects of growth of diamond, which emerged after etching is less than 5·103/mm2.

43. The method according to p, in which the density of surface defects of growth of diamond, onneksi after etching, is less than 102/mm2.

44. The method according to p, in which the surface on which the growth of the diamond is subjected to plasma etching before starting to grow a diamond.

45. The method according to p, in which the growth of diamond occurs on surfaces{100}, {110}, {113} or {111}.

46. The method according to p, in which the boron source is a2H6.



 

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7 cl, 1 tbl, 7 dwg

FIELD: chemical industry; cutting tool industry; mechanical engineering; methods of the production of the artificial highly rigid materials.

SUBSTANCE: the invention is pertaining to production of the artificial highly rigid materials, in particular, diamonds, and may be used in chemical industry; cutting tool industry; mechanical engineering, boring engineering. The method provides for compaction of the powdery carbon-containing materials in the field of the quasi-equilibrium state of the graphite-diamond system and the slow refrigeration in the zone of the thermodynamic stability of the diamond or other synthesized material. The heated capsule made out of tungsten with the pure carbon raw fill in with the liquid silicon at the temperature of 1750°K, hermetically plug up, then reduce the temperature to 1700°K during 30-40 minutes and cool to the room temperature within 5-6 hours in the process of the synthesis of the high-strength materials. The monocrystals of the boron carbide of the 400-450 microns fraction and the diamonds of the 40 microns fraction have been produced. The technical result of the invention consists in improvement of the quality, the increased sizes of the monocrystals, and also in the decreased labor input of the production process.

EFFECT: the invention ensures the improved quality and the increased sizes of the produced monocrystals, the decreased labor input of the production process.

2 cl, 2 ex

FIELD: treatment of diamonds.

SUBSTANCE: proposed method of change of diamond color includes the following stages: (i) forming reaction mass at presence of diamond in pressure-transmitting medium fully surrounds the diamond; (ii) subjecting the reaction mass to action of high temperature and pressure during required period of time; proposed diamond is brown diamond, type IIa; its color is changed from brown to colorless by subjecting the reaction mass to action of temperature of from 2200°C to 2600°C at pressure of 7.6 Gpa to 9 Gpa.

EFFECT: possibility of keeping diamond intact during treatment.

46 cl, 4 dwg, 1 ex

FIELD: treatment of diamonds.

SUBSTANCE: proposed method includes the following stages: (i) forming of reaction mass at presence of diamond in pressure-transmitting medium fully surrounding the diamond and (ii) action of reaction mass by high temperature and pressure during required period of time; diamond is of IIb type and its color is changed from gray to blue or dark blue or is enriched by action on reaction mass of temperature from 1800°C to 2600°C at pressure of from 6.7 GPa to 9 GPa (first version). Diamond of type II may be also proposed which contains boron and its color is changed to blue or dark blue by action on reaction mass by the same temperature and pressure (second version).

EFFECT: improved color of diamond by changing it from gray (brown-gray) to blue or dark blue.

31 cl, 4 dwg, 2 ex

FIELD: treatment of natural diamond for change of its color.

SUBSTANCE: proposed method includes the following stages: (i)forming of reaction mass at presence of diamond pressure-transmitting medium which fully surrounds it; (ii) action on reaction mass by high temperature and pressure during required period of time; proposed diamond is brown diamond, type IIa; its color is changed from brown to rose by action on reaction mass by temperature from 1900°C to 2300°C at pressure from 6.9 GPa to 8.5 GPa.

EFFECT: enhanced efficiency of enriching diamond color keeping its crystals intact.

30 cl, 4 dwg, 1 ex

FIELD: processes and equipment for working natural and artificial origin diamonds, possibly in jewelry for refining diamonds and for imparting to them new consumer's properties.

SUBSTANCE: method comprises steps of acting upon crystal with electron beam whose integral flux is in range 5 x 1015 - 5 x 1018 electron/cm2; annealing crystal in temperature range 300 - 1900°C and acting with electron beam in condition of electric field having intensity more than 10 V/cm at least upon one local zone of crystal for imparting desired color tone to said zone. Local action of electron beams is realized through protection mask. As irradiation acts in condition of electric field local flaws such as bubbles or micro-inclusions are effectively broken.

EFFECT: possibility for producing diamonds with different local three-dimensional colored images such as letters or patterns of different tints and color ranges.

2 dwg

FIELD: advanced techniques for creating diamonds, possibly micro- and nano-electronics for creating new super-strength construction materials widely used in different branches of industry, for producing semiconductor diamond base light emitting diodes, jewelry articles.

SUBSTANCE: diamond synthesis method comprises steps of irradiating carbon-containing materials with fluxes of magnetic mono-fields generated from plasma for time period determined by motion speed of magnetic mono-fields through irradiated material. Such process does not need high-pressure chambers, special heating members and it is possible to realize it at atmospheric pressure and room temperature or in vacuum.

EFFECT: possibility for producing high-purity diamonds of predetermined size and shapes.

8 dwg

FIELD: production of diamonds for electronics.

SUBSTANCE: diamond is produced from gas phase by chemical deposition on diamond substrate whose surface is practically free from any defects in crystal lattice in flow of carrier gas in atmosphere containing nitrogen at concentration lesser than 300 part/109. Diamond thus produced is chemically pure with no defects in crystal lattice at enhanced electronic characteristics as compared with purest natural diamonds.

EFFECT: enhanced purity and improved electronic characteristics.

32 cl, 8 dwg, 1 tbl, 4 ex

FIELD: producing artificial diamonds.

SUBSTANCE: method comprises preparing diamond substrate virtually having no defects, preparing the initial gas, decomposing initial gas to produce the atmosphere for synthesis that nitrogen concentration of which ranges from 0.5 to 500 particles per million, and homogeneous epitaxy growth of diamond on the surface.

EFFECT: increased thickness of diamond.

40 cl, 9 dwg, 5 ex

FIELD: production of diamond layers.

SUBSTANCE: diamond layer at thickness more than 2 mm is obtained through chemical deposition from gaseous phase. Method includes homo-epitaxial growth of diamond layer on surface of backing at low level of defects in atmosphere containing nitrogen at concentration lesser than 300 billion parts of nitrogen.

EFFECT: improved quality of diamond layers.

36 cl, 10 dwg, 1 tbl, 4 ex

FIELD: production of diamonds for electronics.

SUBSTANCE: diamond is produced from gas phase by chemical deposition on diamond substrate whose surface is practically free from any defects in crystal lattice in flow of carrier gas in atmosphere containing nitrogen at concentration lesser than 300 part/109. Diamond thus produced is chemically pure with no defects in crystal lattice at enhanced electronic characteristics as compared with purest natural diamonds.

EFFECT: enhanced purity and improved electronic characteristics.

32 cl, 8 dwg, 1 tbl, 4 ex

FIELD: production of diamond layers.

SUBSTANCE: diamond layer at thickness more than 2 mm is obtained through chemical deposition from gaseous phase. Method includes homo-epitaxial growth of diamond layer on surface of backing at low level of defects in atmosphere containing nitrogen at concentration lesser than 300 billion parts of nitrogen.

EFFECT: improved quality of diamond layers.

36 cl, 10 dwg, 1 tbl, 4 ex

The invention relates to methods of artificial synthesis of single crystals of diamond - like with predetermined physical properties: solid, fluorescent, colored, etc., and without impurities with high optical transparency

The invention relates to the field of deposition of carbon by decomposition of gaseous compounds by microwave plasma-discharge and can be used, for example, polycrystalline diamond films (wafers), from which is produced the output window powerful sources of microwave radiation, such as gyrotrons required for additional plasma heating in fusion devices

FIELD: producing artificial diamonds.

SUBSTANCE: method comprises preparing diamond substrate virtually having no defects, preparing the initial gas, decomposing initial gas to produce the atmosphere for synthesis that nitrogen concentration of which ranges from 0.5 to 500 particles per million, and homogeneous epitaxy growth of diamond on the surface.

EFFECT: increased thickness of diamond.

40 cl, 9 dwg, 5 ex

FIELD: decorative diamond gem-cutting structure and method for evaluating of diamond.

SUBSTANCE: gem-cutting structure is made in the form of round diamond gem-cut comprising rundist, crown above rundist and pavilion under rundist. Height of rundist is 0.026-0.3 the radius of rundist, angle of pavilion of rundist main facet is ranging between 37.5 deg and 41 deg, and angle of main facet of crown is within the range conforming to the following ratios: c>2.8667xp+134.233 and p<1/4x{sin-1(1/n)+sin-1 (1/n˙sinc))x180/π +180-2c}, where n is diamond diffraction ratio; π is circle constant; p is angle of pavilion, deg; c is angle of crown, deg. Decorative diamond cutting design presents multiplicity of visually perceptible diffracted beams, when observer contemplates diamond on the side of pavilion facet at sight angle less than 20 deg relative to vertical line extending through center of facet of platform.

EFFECT: increased number of perceived diffracted beams to impart additional aesthetic attractiveness to diamond.

13 cl, 43 dwg

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