Method for growing silicon-germanium heterostructures
SUBSTANCE: in method for growing of silicon-germanium heterostructures by method of molecular-beam epitaxy of specified structures due to silicon and germanium evaporation from separate crucible molecular sources on the basis of electronic-beam evaporators, silicon evaporation is done in automatic crucible mode from silicon melt in solid silicon shell, and germanium is evaporated from germanium melt in silicon insert, which represents a previously spent hollow residue, produced as a result of silicon evaporation in automatic crucible mode, and arranged in crucible cavity of cooled case of crucible unit of electron-beam evaporator used to develop molecular flow of germanium. At the same time process of epitaxy is controlled with account of germanium deposition speed selection, determined from given dependence.
EFFECT: increased stability and expansion of assortment of generated high-quality silicon-germanium heterostructures as a result of improved control of molecular-beam epitaxy of heterostructures due to accurate control of silicon and germanium deposition mode in the optimal range of speed values, reduction of concentration of uncontrolled admixtures in heterostructures produced by proposed method, and reduction of resource expenditures for preparation of process equipment.
2 cl, 3 dwg
The invention relates to the technology of epitaxial deposition of semiconductor materials on a substrate and can be used to ensure accountability and controllability of the process of vacuum deposition of silicon and germanium from separate electron beam evaporators in the implementation of molecular-beam epitaxy silicon-germanium heterostructures.
Epitaxy of silicon and germanium to form their heterostructures popular modern solid-state micro - and nano-electronics to create microwave devices, optoelectronic devices and circuits, which play an important role layered (and mixed) patterns of submicron size with different chemical composition, in particular on the basis of silicon and germanium (see, for example, U.S. patent No. 4861393, H01L 29/165, H01L 31/06, H01L 21/203, 1989, as well as a book in English. lang. Herman M.A., Sitter H. Molecular Beam Epitaxy Fundamentals and Current Status. Berlin, Springer, 1996, p.286-287, fig.5.32).
Thus the controllability of the deposition processes for forming these structures largely depends on the method of obtaining molecular beams of silicon and germanium.
So when used for evaporation Germany is known of the molecular source based on the Knudsen cell with a crucible of boron nitride, equipped with a heater (see U.S. patent No. 4550411, NV 3/02, 1985), number Zagra the developments made in the grown film structural elements of the source increases dramatically when driven by the requirements of an acceptable deposition rate of the temperature increase of the molecular source (see Belousova T.V. and Sadofyev YG Features of growing germanium on gallium arsenide by the MBE method. Electronics, 1990, No. 10, p.78).
The closest to the technical essence is similar, selected by the applicant as a prototype and represents a method of growing silicon-germanium heterostructures by molecular beam epitaxy of these structures due to the evaporation of silicon and germanium from separate molecular sources based on electron-beam evaporators (see patent EP No. 0276914 A2, SW 23/02, 1988).
However, the drawback of the prototype method is applicable for Germany the so-called mode autothermal evaporation, providing a stable evaporation material. To implement this mode requires that adjacent to the walls of the cooled crucible portion of the evaporated material was in the unfused condition that creates the temperature gradient necessary for a stable evaporation material without splashing (see this article Belousova T.V. and Sadofyev YG, P80). In the case of Germany due to low pressure when the tempo is the atur melting its own vapor to achieve an acceptable rate of deposition of the melt Germany to be heated considerably above the melting temperature. In the result, the entire volume of Germany in the crucible, including the walls of the crucible becomes liquid, and that makes for Germany autothermal mode.
This automically mode of evaporation sell by electron-beam evaporation of silicon, because the pressure of vaporized silicon at the melting point to two orders of magnitude higher than that of Germany at its melting point. The result is an acceptable deposition rate of silicon is achieved when the transition in the molten state, only the Central part of the material in the crucible.
Additional stabilization measures the rate of evaporation Germany, such as the introduction of the graphite insert between germanium and water-cooled metal crucible walls of the unit to reduce the temperature drop of Germany in the center and on the periphery of its melt (see this article Belousova T.V. and Sadofyev YG, P80), did not allow the deposition of Germany with the concentration of electrically active impurities in the formed structure is less than 1016cm-3.
The technical result of the claimed invention - improved stability and expansion of the range to form a high quality silicon-germanium heterostructures as a result of improved control of molecular beam epitaxy these heterostructures due to ensure the ing accurate control of the mode of deposition of silicon and germanium in the optimal interval of values of the velocities of successive and simultaneous deposition, the reduction of the concentration of uncontrolled impurities in the received offer by way heterostructures, as well as reduced resource costs for preparation of process equipment to achieve the specified result due to the proposed modernization of the crucible block electron-beam evaporator.
To achieve the stated technical result in the method of growing silicon-germanium heterostructures by molecular-beam epitaxy of these structures due to the evaporation of silicon and germanium from separate molecular sources based on electron-beam evaporators evaporation of silicon are in autothermal mode from the silicon melt in the solid silicon membrane and evaporation Germany - of germanium in the silicon melt the liner, which represents a previously developed hollow residue resulting from evaporation of silicon autothermal mode, and located in the crucible cavity cooled crucible body unit electron beam evaporator is used to create molecular flux Germany.
The process of epitaxial silicon-germanium heterostructures regulate with regard to choice of baseline for accountability of this process within the provision of high quality heterostructures deposition rate ger the project in accordance with the value
where νGethe deposition rate of the Ge;
rcp- the average radius of curvature of evaporated surface of an ingot of germanium in silicon liner;
R is the distance between the evaporable surface of the ingot of germanium in silicon liner and substrate grown silicon-germanium heterostructures.
When forming the silicon-germanium heterostructures under high vacuum installation molecular-beam epitaxy "BALZERS" UMS 500P at an operating voltage of electron beam evaporators 10 kV and the electron emission current up to 100 mA using a silicon liner having a wall thickness of 5-10 mm to create a temperature gradient between the melt Germany and cooled crucible body unit, which determines the conditions of stable evaporation Germany at the maximum growth rate of the mixed heterostructure of 0.2 nm/sec.
Figure 1 shows the General scheme of the high-vacuum installation molecular beam epitaxy for the implementation of the proposed method of growing silicon-germanium heterostructures; figure 2 - electron-beam evaporator for evaporating Germany as part of the installation of figure 1; figure 3 - x-ray spectrum obtained in accordance with the inventive method, the silicon-germanium heterostructures, confirming precise control of the deposition of silicon and germaniae the formation of the layers of the heterostructure with a given distribution of composition.
The inventive method of growing silicon-germanium heterostructures is carried out using high-vacuum installation molecular beam epitaxy.
For evaporation of silicon and germanium specified installation (see figure 1) equipped with electron beam evaporators 1 and 2 (electron beam evaporator 1 is designed for evaporation of Germany, an electron-beam evaporator 2 for evaporation of silicon), which consists of water-cooled copper crucible blocks 3 and 4.
In crucible cavity block 3 (see figure 2), designed for evaporation of Germany, is a silicon liner 5 in contact with its internal walls with GE 6, placed in turn in the specified liner. Silicon liner 5 is a previously developed hollow residue resulting from evaporation of silicon autothermal mode and uncovered after that of the cavity of the crucible unit 3 electron beam evaporator is used to create molecular flux Germany.
For molecular beam epitaxy of silicon-germanium heterostructures high vacuum installation with moveable flaps 7, allowing you to independently control the molecular beams of silicon and germanium, falling on the substrate 8.
Molecular beam epitaxy silicon-germanium hetero is ructur in vacuum is carried out by evaporation of silicon from the silicon melt in the solid silicon membrane in the crucible unit 4 in autothermal mode and evaporation from Germany germanium melt in a hollow solid silicon the liner 5 in the crucible block 3 (see figure 2) subject to the choice of the value of the deposition rate of Germany in accordance with the proposed applicant for plants of various types (derived from technical installations and patterns of molecular process of evaporation and precipitation) ratio (1) and their deposition at the open flaps 7 on the substrate 8 (see Fig 1).
In the example implementation of the proposed method was used to install "BALZERS" UMS 500P - production firm "Balzers (Liechtenstein).
When forming in the specified installation silicon-germanium heterostructures at an operating voltage of electron beam evaporators 10 kV and the electron emission current up to 100 mA evaporation Germany led from its melt in silicon liner having a wall thickness of 5-10 mm, the wall thickness of the silicon liner needed to create a temperature gradient between the cooled walls of the crucible unit and evaporated germanium for stable evaporation Germany at the rate of deposition (when the distance between the surface of the evaporated Germany and the substrate forming the heterostructure ~ 510 mm), not exceeding 0.1 nm/s
As starting materials for evaporation in electron beam evaporators served as monocrystalline silicon and germanium (with the average radius of curvature of evaporated surface the ingot ~15 mm) with acceptor type conductivity, and boron concentration ≤1·10 15cm-3.
The use of silicon liner is possible to eliminate splashing and dripping Germany during the evaporation of Germany from its melt in such a liner with a volume of its cavity ~3-4 cm3when the volume of the crucible cavity 7.5 cm3.
The result is the ability to lower the level of uncontrolled impurities in the generated structures in comparison with the known method using graphite inserts and greatly improve the stability and controllability of evaporation Germany in the process of their formation in comparison with the method of the prototype. This allowed to significantly improve the stability of the quality of the formed silicon-germanium heterostructures and to obtain structures with the given parameters of the composition and thicknesses of the layers.
3 shows the experimentally measured (curve a) and calculated (curve b) x-ray diffraction spectra from the grating with five periods (Si0.7Ge0.3d=3 nm) / Si d=20 nm), obtained in the vicinity of the peak of Si (004) from the substrate, confirming the good agreement between experimental and calculated spectra, which means that the values match, the composition and thickness of layers in a heterostructure formed with predetermined before growing.
Layer-by-layer analysis of a wide class of grown silicon-germanium heterostructures by means of secondary ion mass-spectra the Mat showed the concentration of impurities of oxygen and carbon in them is at the level of 1·1016÷5·1017cm17that corresponds to the content of these impurities in pure raw materials. The level of electrically active uncontrolled impurities is less than 1015cm-3.
In addition, is provided to reduce the resource costs of preparing installation to achieve a specified result in the identification of additional technology to increase the efficiency of the equipment (silicon liner - residue resulting from evaporation of silicon autothermal mode and uncovered after that of the cavity of the crucible block electron-beam evaporator used in the proposed method to generate molecular flux Germany).
1. The method of growing silicon-germanium heterostructures by molecular-beam epitaxy of these structures due to the evaporation of silicon and germanium from separate molecular sources based on electron-beam evaporators, characterized in that the evaporation of silicon are in autothermal mode from the silicon melt in the solid silicon membrane and evaporation Germany - of germanium in the silicon melt the liner, which represents a previously developed hollow remnant, education is avisa as a result of evaporation of silicon autothermal mode,
and located in the crucible cavity cooled crucible body unit electron beam evaporator is used to create molecular flux Germany, the process of epitaxial silicon-germanium heterostructures regulate with regard to choice of baseline for accountability of this process within the provision of high quality heterostructures deposition rate of Germany in accordance with the ratio:
where νGethe deposition rate of the Ge;
rcf- the average radius of curvature of evaporated surface of an ingot of germanium in silicon liner;
R is the distance between the evaporable surface of the ingot of germanium in silicon liner and substrate grown silicon-germanium heterostructures.
2. The method according to claim 1, characterized in that when forming the silicon-germanium heterostructures under high vacuum installation molecular-beam epitaxy "BALZERS" UMS 500P at an operating voltage of electron beam evaporators 10 kV and the electron emission current up to 100 mA using a silicon liner having a wall thickness of 5-10 mm to create a temperature gradient between the melt Germany and cooled crucible body unit, which determines the conditions of stable evaporation Germany at the maximum growth rate of the mixed heterostructures is 0.2 nm/sec.
SUBSTANCE: invention can be used in manufacturing organic light-emitting diodes, liquid-crystal displays, plasma display panel, thin-film solar cell and other electronic and semi-conductor devices. Claimed is element, including target of ionic dispersion, where said target includes processed MoO2 plate of high purity. Method of such plate manufacturing includes isostatic pressing of component consisting of more than 99% of stoichiometric MoO2 powder into workpiece, sintering of said workpiece under conditions of supporting more than 99% of MoO2 stoichiometry and formation of plate which includes more than 99% of stoichiometric MoO2. In other version of said plate manufacturing component, consisting of powder, which contains more than 99% of stoichiometric MoO2, is processed under conditions of hot pressing with formation of plate. Method of thin film manufacturing includes stages of sputtering of plate, which contains more than 99% of stoichiometric MoO2, removal of MoO2 molecules from plate and application of MoO2 molecules on substrate. Also claimed is MoO2 powder and method of said plate sputtering with application of magnetron sputtering, pulse laser sputtering, ionic-beam sputtering, triode sputtering and their combination.
EFFECT: invention allows to increase work of output of electron of ionic sputtering target material in organic light-emitting diodes.
16 cl, 5 ex
SUBSTANCE: invention relates to vacuum technology and the technology of making carbon nanotubes, such as carbon nanotubes at ends of probes, which are used in probe microscopy for precision scanning. The method of making probes with carbon nanotubes is realised by depositing carbon films with nanotubes through magnetron sputtering in a vacuum at direct current of 100-140 mA using a carbon target with a nanotube growth catalyst. Work pieces of the probes are put into a vacuum installation. A carbon film with nanotubes is then sputtered in a residual atmosphere of inert gas.
EFFECT: invention allows for obtaining probes with carbon nanotubes, lying perpendicular the surface of the probe, in required amounts without using explosive substances and complex devices.
FIELD: electronic engineering; materials for miscellaneous semiconductor devices using gallium arsenide epitaxial layers.
SUBSTANCE: intermetallic compounds chosen from group incorporating tin arsenide SnAs, palladium antimonide PdSb, manganese polyantimonide Mn2Sb, nickel stannate Ni3Sn2, nickel aluminate Ni2Al3, nickel germanate Ni2Ge, and cobalt germanate Co2Ge are used as materials of substrates for growing gallium arsenide epitaxial layers.
EFFECT: enhanced structural heterogeneity of gallium arsenide layers being grown.
FIELD: non-organic chemistry, namely triple compound of manganese-alloyed arsenide of silicon and zinc arranged on monocrystalline silicon substrate, possibly in spintronics devices for injection of electrons with predetermined spin state.
SUBSTANCE: electronic spin is used in spintronics devices as active member for storing and transmitting information, for forming integrated and functional micro-circuits, designing new magneto-optical instruments. Ferromagnetic semiconductor hetero-structure containing zinc, silicon, arsenic and manganese and being triple compound of zinc and silicon arsenide alloyed with manganese in quantity 1 - 6 mass % is synthesized on substrate of monocrystalline silicon and has formula ZnSiAs2 : Mn/Si. Such hetero-structure is produced by deposition of film of manganese and diarsenide of zinc onto silicon substrate and further heat treatment of it.
EFFECT: possibility for producing perspective product for wide usage due to combining semiconductor and ferromagnetic properties of hetero-structure with Curie temperature significantly exceeding 20°C and due to its compatibility with silicon technique.
3 ex, 2 dwg
FIELD: semiconductor technology; production of microelectronic devices on the basis of substrates manufactured out of III-V groups chemical element nitride boules.
SUBSTANCE: the invention is pertaining to production of microelectronic devices on the basis of substrates manufactured out of III-V groups chemical element nitride boules and may be used in semiconductor engineering. Substance of the invention: the boule of III-V groups chemical element nitride may be manufactured by growing of the material of III-V groups the chemical element nitride on the corresponding crystal seed out of the same material of nitride of the chemical element of III-V of group by epitaxy from the vapor phase at the speed of the growth exceeding 20 micrometers per hour. The boule has the quality suitable for manufacture of microelectronic devices, its diameter makes more than 1 centimeter, the length exceeds 1 millimeter, defects density on the boule upper surface is less than 107 defects·cm-2.
EFFECT: the invention ensures manufacture of the microelectronic devices of good quality and above indicated parameters.
102 cl, 9 dwg
SUBSTANCE: in method for generation of nanostructures on substrate, by means of controlled laser action at sample via substrate with gap between sample and substrate, varying parametres of laser radiation and distance between substrate and sample, selection of nanoparticles is carried out, which in process of deposition form a nanostructure on substrate with gap from several microns to 2 mm in air atmosphere.
EFFECT: production of lengthy arrays of nanostructures with the possibility to provide efficient control of shape and alignment of synthesized particles, selection of light and heavy particles to obtain higher homogeneity of nanostructures.
3 cl, 1 dwg
SUBSTANCE: in method of manufacturing of stepped altitude calibration standard for profilometry and scanning probe microscopy, silicon substrate with vicinal surface is placed into vacuum, and thermoelectric annealing is carried out, forming monoatomic steps on surface of substrate, separated with wide terraces with initial surface reconstruction, then substrate is cooled, forming subatomic steps on terraces by provision of neighbouring areas of substrate surface with superstructure reconstruction and areas, which have not been exposed to superstructure reconstruction, but have not remained in the condition of initial surface reconstruction, evenly distributed on surface of substrate, and level of vacuum is maintained as providing for output of substrate material atoms into vacuum during thermoelectric annealing.
EFFECT: invention provides for reproducibility of measurements, increased accuracy of relief features altitude detection, reduced error of measurements, reduced altitude of calibration reference sample.
14 cl, 8 dwg
SUBSTANCE: invention relates to devices for measuring relief, linear dimensions and physical characteristics of the surface of objects using a scanning probe microscope in scanning tunnel microscope and atomic-force microscope modes. In the disclosed device there is possibility of measuring mass of a thin-film sample and dissipative properties of the thin-film sample or liquid medium using piezocrystal microbalances, as well as the possibility of modifying the surface of an object. In the scanning probe microscope combined with a device for measuring mass and dissipative properties, having a unit for controlling the piezocrytal microbalances, a scanning device having a probe holder, a probe, a recording system, a chamber and crystal resonator inside the chamber, where the said crystal resonator has a quartz disc, top and bottom electrodes, there is an optical system, an XYZ positioner and a device for applying voltage between the probe and the top electrode.
EFFECT: broader functionalities of the device.
14 cl, 1 dwg
SUBSTANCE: invention refers to nanotechnologies and can be used for creating two- and three-dimensional self-organising periodic structures of nanocrystals which can be used for obtaining optic grids, optic filters, catalysts and microelectronic structures. Essence of invention consists in the fact that for obtaining two- and three-dimensional self-organising periodic structures of nanocrystals, to return microemissions stabilised with anionic and non-ionic surface-active substances (SAS), in water drops of which there are nanoparticles, there added is the second SAS, nanoparticles are moved to hydrocarbon solvent so that hydrocarbon dispersion is formed; after that, hydrocarbon dispersion is applied to the substrate. At that, as the second SAS there used is s-alkylisothiouronium halogenide (ATH) with length of chain from octile to undecyl and from tridecyl to hexadecyl one.
EFFECT: enlarging the range of used ATH both as to length of chain, and as to counterion.
2 cl, 2 ex, 2 dwg
SUBSTANCE: invention refers to nanostructures and methods of their growth. Method of forming nanostructure provides deposition of pack of layers on conducting substrate and growth of nanostructures on the above pack of layers; at that, the above pack of layers contains at least one intermediate layer and catalyst layer formed on the above at least one intermediate layer, and the above at least one intermediate layer is made from material which differs from the material of the above conducting substrate and material of the above catalyst layer; at that, the above pack of layers contains the materials allowing interdiffusion of the above layers.
EFFECT: obtaining nanostructures with controlled composition and properties.
14 cl, 44 dwg
FIELD: process engineering.
SUBSTANCE: invention relates to plasma chemical synthesis using transformer plasmatron to produce high-quality nanopowders of diverse substances. In compliance with this method, initial stock is fed in liquid or vaporous state, or gaseous state in induction discharge or in plasma jet. Plasma chemical reaction is performed at 1.01×105 Pa and higher, induction discharge frequency of 100-400 kHz and temperature of up to 10000 °C in atmosphere of reducing or oxidising gas. Produced powder is tempered and extracted from reaction zone. Proposed device comprises initial stock feed system, transformer plasmatron, nanopowders tempering system, water-cooled chamber, bag filter and nanopowders collector, all being interconnected.
EFFECT: high-quality nanopowders, efficiency, simple design, safe use.
5 cl, 1 dwg
FIELD: process engineering.
SUBSTANCE: invention relates to equipment designed to mix nanoparticles with loose materials and can be sued in metallurgy or construction. Proposed mixer comprises cylindrical housing with loose materials feeder arranged atop the housing. There is a rotor-type loose material spreader arranged under aforesaid feeder. Conical branch pipe is arranged at housing bottom to unload mix of loose materials with nanoparticles. Air or fluid mechanical injectors communicated with nanoparticles feed injector is arranged under or above aforesaid rotor-type spreader.
EFFECT: higher quality of mixing.
SUBSTANCE: invention relates to nanobiotechnology in field of medicine. Nanodiamond powder with particle size not more than 10 nm is placed in press-form and formed at pressure 50-300 MPa. Formed semi-product is thermally processed in medium of gaseous hydrocarbons during time which ensures obtaining porosity 40-75 vol. %. Inorganic base, made from biocompatible carbon composite material, representing nanodiamond particles, bound by graphite-like carbon, is obtained. Pores of obtained base are filled with medication by soaking with medication solution or medication adsorption from its solution.
EFFECT: invention allows to increase drug container efficiency, extend classes of obtained medications in combination with simplification of technology of its manufacturing.
2 cl, 1 dwg, 3 ex
FIELD: information technology.
SUBSTANCE: protective element for authenticating a security object has a substrate and a metal-coated layer, where the said metal-coated layer is a single-layer or multilayer insular metal-coated layer or a layer made from granular metal, having nonlinear dependency of electrophysical properties when exposed to a weak constant or alternating electric field, and also has a protective dielectric layer deposited on top of the said metal-coated layer. The detected authenticity feature of the security object is nonlinear conductivity of the protective element which is determined by measuring conductivity of the protective element at two different amplitude values of the said electric field applied to the protective element.
EFFECT: more reliable protection and easier checking of protective properties.
5 cl, 4 dwg
SUBSTANCE: composite sintered powder material contains copper powder with grain size of 100-160 mcm, granules of copper-plated graphite with grain size of 160-200 mcm in quantity of 16-17 wt % at copper content in granules of copper-plated graphite of 70-75 wt %, granules of copper-plated polymer with grain size of 50-200 mcm in quantity of 7-9 wt % at copper content in granules of copper-plated polymer of 50-60 wt %, granules of copper-plated nickel with grain size of 100-200 mcm in quantity of 3-5 wt % at copper content in granules of copper-plated nickel of 25-35 wt %, granules of copper-plated chrome with grain size of 25-75 mcm in quantity of 6-8 wt % at copper content in granules of copper-plated chrome of 30-40 wt %, carbon nano-tubes in quantity of 0.2-0.7 wt % and fullerenes in quantity of 0.02-0.04 wt %.
EFFECT: high hardness and low porosity.
FIELD: carbon materials.
SUBSTANCE: weighed quantity of diamonds with average particle size 4 nm are placed into press mold and compacted into tablet. Tablet is then placed into vacuum chamber as target. The latter is evacuated and after introduction of cushion gas, target is cooled to -100оС and kept until its mass increases by a factor of 2-4. Direct voltage is then applied to electrodes of vacuum chamber and target is exposed to pulse laser emission with power providing heating of particles not higher than 900оС. Atomized target material form microfibers between electrodes. In order to reduce fragility of microfibers, vapors of nonionic-type polymer, e.g. polyvinyl alcohol, polyvinylbutyral or polyacrylamide, are added into chamber to pressure 10-2 to 10-4 gauge atm immediately after laser irradiation. Resulting microfibers have diamond structure and content of non-diamond phase therein does not exceed 6.22%.
EFFECT: increased proportion of diamond structure in product and increased its storage stability.