Method of growing single crystals germany
(57) Abstract:Usage: metallurgy of semiconductors. The inventive original germanium melted, add (3-5)10-4wt.% neodymium and pulling a single crystal on a seed crystal. Increase the lifetime of minority charge carriers and reduce the time life of the main charge carriers to the lifetime of minority charge carriers in Germany. The invention relates to the metallurgy of semiconductor materials and can be used to obtain Germany with a high lifetime of minority charge carriers (nand low life time of the main charge carriers to the lifetime of minority charge carriers (K =o/n).The known method of increasing the lifetime of minority charge carriers and reduce the time relationship of life of the main charge carriers and the lifetime of minority charge carriers which consists in growing a single crystal germanium according to the method of floating-zone melting (see the book Glazov C. M., Zemskova Century With Physical and technical principles of doping of semiconductors, M.: Nauka, 1967, S. 331). However, germanium grown by the method of floating-zone melting, has a high energy density, l is the parameters of semiconductor devices, made on the basis of Germany produced using floating-zone melting.The above disadvantages can be eliminated by growing germanium on the well-known Czochralski (Glazov, C. M., Zemskov C. C. Physico-chemical basis for the doping of semiconductors, M.: Nauka, 1967, S. 309). However, not high enough lifetime of minority charge carriers and large coefficients of adhesion TO 103- 104at the temperature of liquid nitrogen (77 K) in such materials to limit its scope, particularly in the manufacture of photovoltaic devices and detectors of ionizing radiation, for which the working temperature range is near 77 K.Also known is a method of growing single crystals of Germany by the Czochralski method characterized in that for the purpose of studying opportunities Ge-doped with properties different from the properties of Ge doped commonly used admixtures, as an alloying agent in the melt is injected alloy Germany with REE (nd). However, the above method cannot get the Ge crystals with controlled electrical parameters, which is typical for crystals grown by the Czochralski method, legs is agenie in the band gap energy levels, resulting from the doping of the refractory alloy Ge-CEA, and secondly, the resulting crystals have a high heterogeneity of the resistivity along the generatrix of the ingot due to the low segregation coefficient (1 of 10-5). In addition, the material obtained in this way, due to the fact that neodymium is introduced into the single crystal in the composition of the alloy, it is present in the crystal in the form of refractory compounds neodymium-germanium (Yatsenko S. P., Fedorov E., Rare-earth elements. Interaction with p-metals. M.: Nauka, 1990, S. 173.), and therefore has no heteronomy properties, contributing to the destruction of recombination-active centers of the crystal. Thus, in this paper it is impossible to increase the lifetime of minority charge carriers and reduce the time relationship of life of the main charge carriers to the lifetime of minority charge carriers in comparison with similar units in Ge single crystals obtained by the Czochralski (Glazov, C. M., Zemskov C. C. Physico-chemical basis for the doping of semiconductors. M.: Nauka, 1967, S. 309).The aim of the invention is to increase the lifetime of minority charge carriers and the decrease of the ratio of the lifetime of enol is achieved by in the process of growing a single crystal by the Czochralski method from a melt containing additive impurity element of the VA group of the Periodic system, in the melt is added additive impurity rare-earth element neodymium.The essence of the invention is that due to the high efficiency of interaction introduced into the melt of neodymium with residual process impurities, increases the degree of purification of the melt, i.e., the neodymium atoms in the melt act as an internal getter. In the grown crystal has a lower concentration recombination active centers and centers of adhesion than that of the crystal grown without additives and melt neodymium, which determines for him the high lifetime of minority charge carriers and low-ratio life time of the main charge carriers to the lifetime of minority charge carriers.The content of neodymium in the melt should not be less than 310-4wt.%, as at lower concentrations does not increase nand reduction of K. it is found Experimentally that increasing the lifetime of minority charge carriers in 35010% at T=293 K and 68010% at T=77, and the decrease of the ratio of the times is kristallov happens when introduced into the melt of neodymium in an amount of about 410-4wt.%. Further increase in the concentration of neodymium in the melt over 510-4wt.% and up to 210-2wt.% does not improve these characteristics. When the concentration of neodymium in the melt above 210-2wt.% the lower part of the crystal is not suitable for device fabrication, because it has a modular structure. Based on the objectives to maximize the purity of the crystal and save the materials used, the weight range of the content of neodymium in the melt should be chosen in the range (3-5)10-4wt.%.P R I m e R 1. In the "Subject 10 in the melt Germany weighing 0.5 kg injected 6,6510-6g orthophosphate neodymium as an alloying agent, providing doping Germany phosphorus. Cultivation produced by the Czochralski method in a vacuum of 10-5ATM. with a rate of 0.9 mm/min Crucible rotates with a speed of 7 rpm, and a seed crystal 20 rpm From a single crystal were fabricated samples sizes HH mm Measurement of electrical and recombination parameters showed that samples have e-type conductivity with a specific resistance =10 Ohms see the Value of nhad the value 6 410-5since at T=293 K and 2,4210-7since at T=77 K, and the ratioo/nthe value 1,410who in example 1, but from a melt containing 0.5 kg of Germany, 6,6510-6g orthophosphate neodymium, as alloying additives, and optionally 1,710-3g of neodymium, which is 3,410-4wt.4%, were produced by the same measurement as in example 1. We obtained the following values: a =10 Ohm cm;n= 2,3910-4since at T=293 K and 1,6510-6since at T=77 K;o/n=7,4101at T=77 K.P R I m e R 3. On the single crystal germanium obtained by the method similar to example 1, but from a melt containing 0.5 kg of Germany, 6,6510-6g orthophosphate neodymium, as alloying additives, and optionally 1,0610-2g of neodymium, which is 2,110-3wt.%, were made the same measurements as in example 1. We obtained the following values: a =10 Ohm cm;n=2,1510-4since at T=293 K and 1,1110-6since at T=77 K;o/n=9.8101at T=77 K.P R I m e R 4. On the single crystal germanium obtained by the method similar to example 1, but from a melt containing 0.5 kg of Germany, 6,6510-6g orthophosphate neodymium, as alloying additives, and optionally 510-4g of neodymium, which is 110-4wt.%, were made the same measurements as in example 1. We obtained the following values: a =10 Ohm cm;n= 7,510-5with single crystal germanium way similarly to example 1, but from a melt containing 0.5 kg of Germany, 6,6510-6g orthophosphate neodymium, as a dopant, and an additional 110-1g of neodymium, which is 210-2wt.%, the lower third of the crystal had a large structure.As can be seen from example 2, the application of the proposed method, which consists in introducing into the melt neodymium, allows in Germany, grown by the Czochralski method, to increase the lifetime of minority charge carriers and reduce the time life of the main charge carriers to the lifetime of minority charge carriers in comparison with the prototype (example 1), which is the base object. Example 3 shows that increasing the concentration of neodymium in the melt up to 210-3wt.% does not lead to further increase of the lifetime of minority charge carriers. Therefore, based on task to maximize the lifetime of minority charge carriers and reduce the coefficient of adhesion in Germany, and also in order to conserve rare earth element, the optimal weight range of the content of neodymium in the melt is selected in the range (3-5)10-4wt.%. The proposed method allows to obtain a material for Ashotovich high value of the lifetime of minority charge carriers and low-ratio life time of the main charge carriers to the lifetime of minority charge carriers determining influence on improving the operational parameters of the devices. A METHOD of GROWING single CRYSTALS of GERMANY, including the melting of the source Germany, the introduction into the melt additive containing neodymium, and pulling the single crystal on a seed crystal, wherein, to increase the lifetime of minority charge carriers and reduce the time relationship of life of the main charge carriers to the lifetime of minority charge carriers in single crystals of germanium, neodymium is added to the melt in the amount of (3 - 5) 10-4wt.%.
FIELD: crystal growth.
SUBSTANCE: method comprises crystal growing in two stages: growing alloyed crystals used for making blanks of seeds made of a disk of a given diameter and approximately 5-6-mm thick and subsequent growing of nominally pure crystals.
EFFECT: enhanced quality of crystals.
FIELD: production of solar batteries, integrated circuits and other semiconducting devices.
SUBSTANCE: the invention presents a method of production of alloyed monocrystals or polycrystals of silicon and may be used in production of solar batteries, integrated circuits and other semiconductor devices. The substance of the invention: the method of SUBSTANCE: the invention presents a method of production of alloyed monocrystals or polycrystals of silicon includes preparation of the initial charge consisting of 50 % of silicon alloyed with phosphorus with a specific electrical resistance of 0.8-3.0 Ohm·cm or boron with specific electrical resistance of 1-7 Ohm·cm, its melting-down and consequent growing of crystals from the melt, in which additionally enter elements of IV group from the periodic table by Mendeleyev, in the capacity of which use germanium, titanium, zirconium or hafnium use in concentrations of 1017-7·1019 cm-3. The invention allows to produce chips with high values of life time of minority carrier (LTMC), high homogeneity of electric resistivity (ER) and high concentration of oxygen, with a low concentration of defects and increased thermostability and radiation resistance.
EFFECT: the invention ensures production of chips with high values of LTMC, high homogeneity of ER and high concentration of oxygen, with a low concentration of defects and increased thermostability and radiation resistance.
2 cl, 4 ex, 1 tbl
FIELD: crystal growing technologies.
SUBSTANCE: invention relates to technology of growing crystals for passive laser shutters used in modern lasers operated in IR spectrum region. Crystals are grown according to Chokhralsky method from initial stock melt containing metal oxide mixture, namely produced via solid-phase synthesis gallium-scandium-gadolinium garnet of congruently melting composition with magnesium and chromium oxide additives assuring concentration of chromium and magnesium cations in melt 2.0·1020 to 2.6·1020 at/cm3. Process is carried out at cell pressure 1.4 atm in argon and carbon dioxide medium with carbon dioxide content 14-17% by volume. Invention makes it possible to grow perfect crystals of gallium-scandium-gadolinium garnets alloyed with chromium cations, which are characterized by absorption coefficient above 5 cm-1 within wavelength 1.057-1.067 μm generation range.
EFFECT: achieved required Q-switching mode in continuous and pulsed operation conditions.
FIELD: chemistry; passive Q-switch crystal growing process.
SUBSTANCE: production process for growing crystals of galium scandium gadolinium garnets is based on Czochralski process, which implies crystal growing from initial molten batch, which is congruently melting gallium scandium gadolinium garnet produced by 3-phase synthesis, doped with magnesium oxide and chromium oxide. These oxides provide for 2.0×1020-2.6×1020 atoms/cm3 concentration of cromium and magensium cations in melt during the first crystal growing, in argon with 14-17% of carbon dioxide, pressure in chamber being 1.3-2.0 atm. For the second, third and subsequent growths, an initial batch amount equal to previous crystal weight, cromium and magnesium content in batch being determined according to formula (СCr×СMg)/1020 = 0.5÷2, where СCr is at least 5×1019 atoms/cm3, is added to the crucible.
EFFECT: provides for required Q-switched mode, continuous or pulse, within wavelength range of 1,057-1,067 mcm.
FIELD: technological process.
SUBSTANCE: invention is related to growing of garnets single crystals and may be used in laser equipment, magnet microelectronics (semi-conductors, ferroelectrics) and for jewelry purposes. Single crystals of terbium-gallium garnet are prepared by Chochralski method by means of melting primary stock, which includes clarifying calcium-containing additive, and further growing of single crystal from melt to primer. As primary stock mixture of terbium and gallium oxides is used, as calcium containing additive - calcium oxide or carbonate, and after growing crystal is annealed in atmosphere of hydrogen at temperature of 850-950°C for around 5 hours until orange paint disappears.
EFFECT: allows to prepare optically transparent homogeneous crystals.
SUBSTANCE: invention relates to the technology of growing monocrystals using Chokhralsky method. Growth of doped crystals of lithium niobate with composition close to stoichiometric is done on an inoculating crystal from molten mixture of lithium niobate of identical composition with ratio Li/Nb equal to 0.938-0.946 and containing 9-13 mol % K2O and 0.5-2.5 mol % MgO or ZnO, in conditions of applied electric field with current density of 0.2-40 A/m2. A device is provided for realising the method, comprising a housing with a growth station and a cooling chamber, crucible 1, placed in the growth station, induction heater, top metallic heating shield 4, fitted above the crucible 1, mechanism for moving the crystal with a coupling rod, a rod with a holder 3 for the inoculating crystal 2. The device is also provided with a regulated direct current source 10 with electrodes; under the inoculating crystal 2 there is an additional load from electrically conducting material, separated from the wall of the holder by electrically insulating material. One of the electrodes is connected to the crucible 1, and the second - to the load.
EFFECT: invention allows for growing large optically homogenous crystals of lithium niobate with composition close to stoichiometric Li/Nb>0,994, additionally doped with MgO or ZnO, composition of which in the top and bottom parts of the crystal is virtually the same, without destroying the inoculating crystal.
5 cl, 2 ex, 2 dwg
SUBSTANCE: invention relates to production of silicon monocrystals by Czochralski method or silicon multicrystals by method of directed crystallisation to be used in making solar cells and modules with higher operating performances. Proposed method comprises preparing initial mix alloyed with boron and its melting. Note here that aluminium is added to produced melt in amount sufficient for allow ratio between concentrations of aluminium and oxygen equal to 1-102.
EFFECT: p-type conductance silicon with low concentration of oxygen.
FIELD: physics, optics.
SUBSTANCE: invention relates to the technology of producing a terbium aluminium garnet single crystal which can be used as a polarisation rotator (Faraday rotator) in optics. The single crystal is a terbium aluminium garnet single crystal in which part of the aluminium is replaced with lutetium (Lu) and which has the following chemical formula:
EFFECT: invention increases the size of obtained crystals.
10 cl, 9 dwg, 4 ex
SUBSTANCE: invention relates to production of semiconductor materials and specifically to production of gallium antimonide monocrystals, which are used as substrate material in isoperiodic heterostructures based on ternary or quaternary solid solutions in Al-Ga-As-Sb and In-Ga-As-Sb systems, which enable to produce a wide range of optoelectronic devices (radiation sources and detectors in the 1.3-2.5 mcm spectral range). The method includes synthesis and growing a monocrystal using a Chochralski method in a hydrogen atmosphere on a seed crystal in the  crystallographic direction, wherein synthesis of the monocrystal is carried out in a single process with the flow rate of especially pure hydrogen in the range of 80-100 l/h and holding the melt at the synthesis step at 930-940°C for 35-40 minutes.
EFFECT: invention enables to obtain perfect large-size gallium antimonide monocrystals with diameter of 60-65 mm.
SUBSTANCE: invention relates to field of obtaining semi-conductor materials, which are applied as substrate material in isoperiod heterostructures based on triple and fourfold solid solutions in systems Al-Ga-As-Sb and In-Ga-As-Sb, which make it possible to create broad range of optoelectronic devices (sources and receivers of irradiation on spectral range 1.3-2.5 mcm). Method includes synthesis from initial components and growing of monocrystals by method of Czochralski in hydrogen atmosphere on seed, oriented in crystallographic direction . To initial components added is isovalent admixture of indium in form of especially pure indium antimonide (InSb) in the interval of elementary indium concentration (2-4)×1018 at/cm3, with synthesis and growing of monocrystals being realised in single technological cycle.
EFFECT: invention makes it possible to obtain big-volume low dislocation density monocrystals of gallium antimonide with reduced dislocation density.
2 cl, 1 dwg, 2 tbl, 1 ex
FIELD: crystal growing.
SUBSTANCE: method comprises growing germanium monocrystals from melt onto seed followed by heat treatment, the latter being effected without removing monocrystals from growing apparatus at temperature within 1140 and 1200 K during 60-100 h, temperature field being radially directed with temperature gradient 3.0 to 12.0 K/cm. Once heat treatment comes to end, monocrystals are cooled to 730-750°C at a rate of at most 60-80 K/h. Monocrystals are characterized by emission scattering at wavelength 10.6 μm not larger than 2.0-3.0% and extinction not higher than 0.02-0.03 cm-1, which is appropriate for use of monocrystals in IR optics.
EFFECT: allowed growth of germanium monocrystals with high optical characteristics.
FIELD: growing germanium monocrystals.
SUBSTANCE: germanium monocrystals are grown from melt on seed crystal with the use of molder filled with melt; molder has holes for removal of excessive melt formed during crystallization. First, crystal is enlarged on rotating seed crystal in radial direction till it gets in contact with molder placed in crucible without melt; then, rotation of crystal is discontinued and crystallization is carried out in axial direction by lowering the temperature till complete hardening of melt; molder is provided with holes in its lower part located at equal distance from one another at radius r satisfying the condition r<K/h, where K= 0.2 cm2; h is height of melt, cm; number of holes, 12-18. Molder may be made in form of round, square or rectangular ferrule. Proposed method makes it possible to obtain germanium crystals of universal shape with no defects in structure, free from mechanical stresses and homogeneous in distribution of admixtures.
EFFECT: increased productivity; reduced technological expenses; increased yield of product.
2 cl, 2 dwg, 2 ex
FIELD: technological processes.
SUBSTANCE: method includes growing alloyed single crystals of germanium from melt in crucible to crystallographically oriented priming powder, with diameter that is equal to internal diameter of crucible, under conditions of thermal axial flow next to crystallisation front - by OTF method, with application of background heater and double-section heater immersed in melt (OTF-heater) by means of displacement of crucible with priming powder and growing crystal in cold zone of furnace in respect to OTF-heater, which is maintained at constant temperature, with presence of different initial concentrations of alloying admixtures C1 and C2 in melt zones W1 and W2, with thickness of melt layer h in zone W1. Control of crystallisation front shape is carried out simultaneously by OTF- and background heaters, at that in the process of crystal pulling crucible bottom temperature T4(t) is reduced according to the following law: T4(t)=T4 0-axt, where T4 0 - initial value of temperature, a=v(λr×gradTp+Q)/λcr, v - rate of crystal pulling, λr - heat conductivity of germanium melt, gradTp - axial gradient of temperature in melt, at which crystal is grown, Q - crystallisation heat, λcr - heat conductivity of germanium crystal, value h is selected from the condition h<0.3D, where D - diameter of OTF- heater, and ratio of initial concentrations C1 and C2, accordingly, in zones W1 and W2 satisfies condition C1-C2/K, where K - equilibrium coefficient of segregation for used alloying admixture. Method permits to produce alloyed single crystals of germanium with diameter of up to 76 mm without growth strips with high transverse macro-homogeneity of resistance distribution: 1.5-2.5%.
EFFECT: production of single crystals with improved characteristics.
5 cl, 1 ex, 2 dwg
SUBSTANCE: invention relates to growing doped germanium monocrystals in a temperature gradient using a heating element immersed in a melt under conditions of an axial heat flow near a crystallisation front (OTF method). The doped germanium monocrystals are grown from a melt in a crucible placed on a heat-removing unit to an crystallographically directed innculant with diametre equal to the inner diametre of the crucible, under conditions of axial heat flow near the crystallisation front - OTF method, using a multi-section background heater and a multi-section immersed in the melt - OTF-heater kept at constant temperature T1 by moving the crucible with the inoculant and growing crystal into the cold zone of the furnace relative the OTF-heater, with different initial concentrations of doping impurities C1 in the crystallisation zone W1 with height of the melt h, and C2 in a replenishment zone W2, and with reduction of temperature of the bottom of the crucible T4(t) when moving, in accordance with the law: T4(t)=T4 0 -a×t, where T4 0 is initial temperature value, a=v(λm×gradTp+Q)/λcr, v is drawing rate of the crystal, λm is thermal conductivity of molten germanium, gradTp is axial temperature gradient in the melt in which the crystal is grown, Q is crystallisation heat, λcr is thermal conductivity of the germanium crystal. Mass transfer of the melt is controlled in the crystallisation zone by selecting optimum ratio between axial temperature gradient in the melt gradTp, radial distribution of temperature along the OTF-heater, height of the layer of the melt h and drawing rate v. Germanium monocrystals are grown in crystallographic dirctions  and  depending on diametre of the crystal and required quality given the following parameters: h=5-30 mm, gradTp=3-50°C/cm, v=2-30 mm/h, temperature difference of the OTF-heater T2-T1=0-6°C, temperature difference between the lateral surface of the crucible T3 and temperature of the OTF-heater T2, equal to T3-T2=1-20°C.
EFFECT: obtaining germanium monocrystals with diametre of up to 150 mm without growth region with high cross sectional macro-uniformity of distribution of resistance of 5-10%.
10 cl, 1 ex, 2 dwg
SUBSTANCE: profiled monocrystals of germanium are grown on seed crystal from liquor with application of shape-former, placed in crucible and having holes in the place where its lower part adjoins crucible bottom for removal of excessive liquor; first initial charge of germanium is placed into shape-former and space between crucible wall and shape-former and melted, with height of liquor in said space being at the level 0.85÷0.95 of height of liquor in shape-former, after that, seed crystal rotating with angular speed in the range 5÷20 rev/min is placed into liquor of shape-former, and crystal is grown in radial direction until its diameter approaches diameter of shape-former, then rotation of crystal is stopped, regulated reduction of temperature to complete crystallisation of entire liquor volume in shape-former with formation of its excess and flowing of liquor through holes of shape-former into space between crucible and shape-former is carried out, after which entire volume of liquor in space between crucible and shape-former is crystallised by further reduction of temperature.
EFFECT: increased yield of suitable production due to obtaining monocrystals of germanium of universal shape without structural defects, free of mechanical stress, and simplification of technological process.
2 cl, 1 dwg, 2 ex
SUBSTANCE: germanium monocrystals are grown in crystallographic direction  after holding at melting point for 1-2 hours, with temperature gradient at the crystallisation front in the range of (10.0÷18.0) K/cm, which provides dislocation density on the level of (2·104-5·105) per cm2.
EFFECT: invention enables to obtain germanium monocrystals with considerable increase in signal reception area due to directed introduction of a given concentration of dislocations into the grown crystal and conversion of said dislocations from standard crystal defects to active elements of infrared optical devices.
3 dwg, 1 tbl
SUBSTANCE: this process comprises growing of germanium crystals from the melt containing the main alloying admixture, stibium, and two extra admixtures, silicon and tellurium, added to the melt in amounts to their concentration therein of 0.5·1020-1.2·1020 cm-3 and 1·1019-5·1019 cm-3, respectively.
EFFECT: higher thermal stability of optical properties.
SUBSTANCE: claimed device comprises crucible 2 arranged in growing chamber 1 with adjacent heater 4 and heat insulator 5, seed holder 3 and thermal hollow above-crucible cylindrical shield 6. The latter is made of low-heat-conductivity material (quartz) fitted at crucible 2 from above to allow its lower part to be immersed in the melt. Said lower part has through cutouts. Note here that each of lower edges of said cutouts represents a line shaped to Archimedean arc or logarithmic spiral.
EFFECT: lower and more stable temperature gradient over crystallisation front and inside single crystal, higher quality of grown crystal.
2 cl, 2 dwg
SUBSTANCE: when drawing, linear displacement of the crystal is carried out at a rate of 0.6-0.9 mm/min in cycles, wherein monocrystals are drawn from a melt upwards, followed by lowering the monocrystal into the melt. The ratio of linear displacement upwards and downwards is 2:1. The value of absolute displacement upwards h in one cycle is calculated using a mathematical formula of the ratio of the crucible diameter to the crystal diameter, in mm: h is less than or equal to 1.5Dcrucible/Dcrystal.
EFFECT: method enables to obtain germanium crystals with a low dislocation density.
SUBSTANCE: before beginning growth process germanium melt is kept in crucible at temperature of melting for 1-2 h. After that, growing germanium monocrystals in crystallographic directions  or  is realised with overcooling at crystallisation front within 0.5-1.0K, rate of radial growth not higher than 0.5 mm/min and temperature gradient at crystallisation front within 3.0-10.0 K/cm.
EFFECT: invention makes it possible to obtain germanium monocrystals with minimal scattering of received infrared radiation not more than 1,0-2,0 percent of received signal power.