Device for growing single crystals
(57) Abstract:The invention relates to methods of obtaining crystals by the Czochralski method using recharge melt the source material. Provides increased output dislocation crystals and reduce energy consumption. The device contains a camera of the growth crucible to melt with the spacer, heater and a means of feeding the melt. The heater has a protrusion in the form of a ring located above the melt. The heat transfer to the melt in the feed area of the granules is direct radiation. This increases the symmetry of the temperature field in the melt. 1 C.p. f-crystals, 1 Il. The alleged invention relates to technologies for semiconductors single crystals by Czochralski method.A device for manufacturing a silicon single crystal containing a growing chamber, a crucible for melting, which is the spacer ring, heater, and system heat shields (see the application of EPO, N 0390503, MKI C 30 B 15/12, 1990.)
In the known device in the zone of introduction of the feed material (outside spacers) significantly reduced the temperature of the melt, because the granules rasped crystals with dislocation structure.This heat pellet is an indirect radiation from the radial heater, which requires substantial energy consumption. In addition, the presence of horizontal screen with a hole whose diameter commensurate with the diameter of the crystal reduces the radiation from the melt surface, however, this reduces the axial temperature gradient, and hence the growth rate of the crystal, which reduces the performance of the device.A device for growing single crystals, including the growing chamber, a crucible for the melt located therein a spacer ring mounted on thermal screen installed coaxially to the crystal, thermal insulation system, and means for supplying granular material in the melt (see U.S. patent N 1936949, IPC C 30 B 15/12, 1990).This device is the closest proposed and accepted by the authors for the prototype.The device prototype resolved the heat sink issue from the melt surface in the zone of crystal growth due to the introduction of a heat shield mounted coaxially to the growing crystal.However, he has all the disadvantages of similar, related to the asymmetry of thermal field generated in the area Panie high crucible requires additional power consumption for heating the top.The essence of the proposal is that in the device for growing single crystals, including the growing chamber, a crucible for melting, which is the spacer ring mounted on thermal screen installed coaxially to the crystal, a heater, a thermal insulation system, and means for supplying feed material to the melt, the upper part of the heater is provided with a horizontal ledge in the form of a ring placed over the melt, the inner diameter of the ring is 0.6 0.9 diameter of the crucible, and a thickness of 0,6 - 1,0 thickness of the heater. The ring may have a variable width and thickness.In the proposed device the annular ledge of the heater is located above the melt, allows direct radiation to transfer heat to the melt surface located on the outer side of the barrier ring, which leads to the reduction of energy consumption for melting of the granules and increases the symmetry of the temperature field in the melt. In addition, to ensure the symmetry of the temperature field in the area of introduction of pellet feed material melt a few heated by increasing the temperature on the ledge of the heater. This is achieved by changing the resistance around the circumference of the ledge, nab the RA ring and the diameter of the crucible, the thickness of the rings and the thickness of the heater is obtained experimentally. When the inner diameter of the ring < 0.6 diameter of the crucible is impossible to install the heat shield around the growing crystal used to create a temperature gradient required for crystal growth. When the inner diameter of the ring greater than 0.9 diameter of the crucible, it has almost no influence on the surface temperature of the melt, i.e. is not overheating. When the thickness of the ledge, the lesser of 0.6 thickness of the heater overheating occurs the periphery of the melt crucible, reduced axial temperature gradient, and hence the growth rate of the crystal, which, in turn, reduces the performance of the installation. When the thickness of the ledge, greater 1,0 thickness of the heater, reducing the efficiency of the heating of the melt, resulting in the occurrence of thermal asymmetry in the melt and reducing dislocation crystals. Thus, the proposed device provides higher output dislocation crystals by increasing the symmetry of the temperature field and the reduction of energy consumption.The drawing shows a diagram of an apparatus for growing single crystals.The device is part of the ring 4, which divides the volume of the melt on the inner part 5 of the growth zone and the outer part 6 - the recharge zone. Spacer ring 1 is made of quartz and is fixed on thermal screen 7 installed coaxially to the growing crystal 8. The crucible 2 is placed in the cavity of the heater 9, having a horizontal ledge 10 in the form of a ring located on the outer part 6 of the melt. The device also has a thermal insulation system 11 and the tool feeding of the melt 12.The device operates as follows.The source material is loaded into the crucible 2, then seal and vacuum growth chamber 1 includes a heater 9 and melted the download. After this, put a seed crystal in the melt and are growing a single crystal while maintaining a constant melt level throughout the crystal growth process by filing in the melt granules feed material. In this case, due to the protrusion 10 of the heater 9, the heat transfer to the outer part of the melt is direct radiation. To ensure the symmetry of the temperature field on the ledge 10 of the heater 9 through the selection of its resistance creates a higher temperature than the heater, small overheating of the melt to the melting of the proposed device were obtained silicon single crystals with a diameter of 125 mm and a length of 1.2 m While the yield on crystals brand EFC-4,5 amounted to 60% which is approximately twice the output of similar crystals obtained on the device prototype, and specific energy consumption in half. 1. Device for growing single crystals, including the growing chamber, a crucible for melting, which is the spacer ring mounted on thermal screen installed coaxially to the crystal, a heater, a thermal insulation system and means for supplying feed material in the crucible, characterized in that the upper part of the heater is provided with a horizontal ledge in the form of a ring placed over the melt, the inner diameter of the ring is 0.6 0.9 diameter of the crucible, and the thickness of 0,6 1,0 thickness of the heater.2. The device under item 1, characterized in that the ring has a variable width and thickness.
FIELD: devices for continuous grouped growing of the orientated layers of silicon on a carbonic fabric.
SUBSTANCE: the invention is pertaining to the field of growing of polycrystallic layers from a melt of silicon and may be used in production of solar cells (photo-converters) Substance of the invention: the device consist of a crucible for a melt mounted inside a heater, a substrates connected to gears of their relocation and a capillary feeding mechanism. The substrates are made out of a carbonic reticulated fabric, and the capillary feeding mechanism consists of two horizontal sections, located to the left and to the right of the crucible, each of which has a tail swathed by harnesses out of a carbonic thread. The crucible is made with the bottom hollow elongated spout supplied with an independent heater, under the crucible there is a tank for a drain of the crucible residue, the inner surface of which is coated by a layer of a hexagonal boron nitride, and above the crucible a vibrating feeder for feeding the ground silicon is mounted.
EFFECT: the invention ensures growing of polycrystallic layers from a melt of silicon.
FIELD: growing lanthanum-gallic silicate monocrystals for making devices on spatial and surface acoustic waves and various piezo-electric and piezo-resonance transducers.
SUBSTANCE: lanthanum-gallic silicate monocrystals (langasite) are grown from charge of the following composition: La3Ga5Si0.88-0.92Ge0.12-0.08O14 (5.387-5.631 wt-% SiO2; 0.404-0.606 wt-% GeO2) in growth unit CRYSTAL-3M including loading the charge into iridium crucible, melting of charge and growth of langasite crystals on preliminarily oriented seed. Use of charge at partial replacement of silicon by germanium reduces oxygen vacancies in langasite crystals improving their quality and making them suitable for manufacture of stable units working at high temperatures.
EFFECT: enhanced efficiency.
FIELD: electronic industry; methods of production of the crystals with the triclinic crystal system.
SUBSTANCE: the invention is pertaining to the method of production of the crystals with the triclinic crystal system. Substance of the invention: the monocrystals of lanthanum-gallium silicate grown in compliance with Czochralski method from the iridium crusible are subjected to the two-stage thermal treatment. The monocrystals are preliminary subjected to the vacuum annealing at the pressure of 1·10-2 -1·10-4Pa and the temperature of 600-1200°C within 0.5-10 hours, and then conduct their isothermal air aging at the temperature of 300-350°C within 0.5-48 hours. The invention allows reproducibly produce the discolored monocrystals of lanthanum-gallium silicate and also to speed up propagation of the surface-acoustic waves (SAW) by 1-1.5 m\s at the simultaneous decrease of dispersion of the waves propagation velocity by 20-30 ppm.
EFFECT: the invention ensures production of the discolored monocrystals of lanthanum-gallium silicate and allows to increase the speed of propagation of the surface-acoustic waves at simultaneous reduction of the waves propagation dispersion by 20-30 ppm.
FIELD: crystal growing.
SUBSTANCE: invention relates to preparation of chrysoberyl monocrystals and its varieties, including alexandrite - chromium-containing variety, which can be used for manufacturing high-quality faceting material in jewelry industry and for manufacturing quantum electronics elements. Growing of bulk chrysoberyl monocrystals and its varieties comprises melting starting blend, homogenizing melt, adding rotating monocrystalline seed, and growing crystal at temperature below phase transfer temperature. Starting blend contains elevated stoichiometric amount of one of its components, namely beryllium oxide by 3-6% or aluminum oxide by 5-6%, with corresponding reduction of content of other constituent. Growing of crystal is conducted under temperature lowering regime at a rate of 0.5-4°C/h, including lowering temperature below eutectic temperature. Starting blend may contain B3+ or Si4+ cations in the form of corresponding oxides in amount of 0.3-0.5%.
EFFECT: enabled growing of defectless chrysoberyl monocrystals at high mass growth rate.
2 cl, 1 dwg, 2 ex
FIELD: technological process.
SUBSTANCE: invention is related to the field of crystals growing and may be used in electronic, chemical industries, in jewelry-making. Method consists in melting of primary stock, seeding onto rotating primer, growing of crystal conical part and crystal pulling. As primary stock mixture of terbium and gallium oxides mixture, after conical part growing has been commenced, the speed of single crystal pulling from melt is reduced according to the following dependence vL=v0-kL, where vL - speed of pulling at crystal length L, mm/hr, v0 - speed of pulling at the beginning of crystal conical part growing, which is equal to 2-7 mm/hr, L - current value of crystal length, mm, k - proportionality constant, which is equal to 0.1-0.2, at that angle of conical part growing is at least 140°.
EFFECT: allows to prepare homogeneous crystals with minimum concentration of defects and increased output of available cylindrical part.
FIELD: technological processes.
SUBSTANCE: invention is related to technology of single crystals LiNbO3 production of stoichiometric composition, which is used in non-linear optics. Single crystals LiNbO3 are melted incongruently, therefore, for production of single crystals of stoichiometric composition, single crystal pulling is used from liquid phase of eutectic composition with make-up of solid phase of preliminarily synthesised compound, which is heated from bottom and top by double-layer spiral electric heater, which is immersed in liquid phase and installed with gap in respect to making-up solid phase, and reduction of temperature gradients in liquid phase and in produced single crystal is performed by application of furnace for single crystal heating. Device includes mechanism of single crystal pulling, thermally insulated crucible with make-up solid phase, flat heater of crucible with thermal insulation, double-layer spiral electric heater with cross-section of spirals in the form of reverse chutes that overlap all section of crucible, which is installed with gap in respect to make-up solid phase, at that double-layer spiral electric heater is equipped with electrodes that pass through furnace thermal insulation for single crystal heating and are fixed to it. Device heaters form flat isothermal surfaces along crucible height, double-layer spiral electric heater with cross section of spirals in the form of reverse chutes that overlap all section of crucible, removes air bubbles that are produced during dissolution of make-up solid phase, from crystallisation front to crucible walls, installation of double-layer spiral electric heater with gap in respect to make-up solid phase provides its heating up to temperature of dissolution provided that temperature gradients in liquid phase and single crystal are reduced, which is achieved by application of furnace with thermal insulation for heating of pulled single crystal, which enters the crucible as make-up dissolves and single crystal is growing.
EFFECT: stabilisation of growth diffusive mechanism performance conditions, reduction of thermal stress in single crystal.
2 cl, 1 dwg
SUBSTANCE: invention refers to borate-based material production technology for crystal growing from caesium borate or caesium-lithium borate which can be used as optical devices for wavelength transformation, in particular, laser generator. Method of crystal growing from caesium borate or caesium-lithium borate includes water dissolution of water-soluble caesium compound and water-soluble boron compound to produce aqueous solution, water evaporation from aqueous solution with or without baking to produce material for crystal growing, and melting of produced material to grow crystals from caesium borate. To grow crystals from caesium-lithium borate water-soluble caesium, lithium and boron compounds are used as initial components of raw material for growing.
EFFECT: invention allows for crystals grown from borate with excellent uniformity and reliability, with small consumptions and for the short period of time; besides, use of this crystal as optical device for wavelength transformation makes it possible to produce very reliable laser generator (laser oscillator).
13 cl, 4 ex, 21 dwg
SUBSTANCE: invention concerns technique of receiving single crystal field by means of method of growth from melt. Method of furnace feed additional charging at growing of silicon single crystals by means of Czochralski method includes charge feeding on the melt surface in capsule from container with charged furnace feeding, where it is provided ability of charge feeding dose on the melt surface through the bottom end, dumping of container till the melt surface in capsule, melt temperature pulldown till formation on the surface of viscous layer of melt, interfere with feeding of unfused charge into melt volume, after what container is opened and charge portion is poured onto viscous layer surface. Then melt temperature is gradually applied till total melting of charged furnace feed, after what empty (or partially discharged) container is taken out from the growth region, to its place it is dropped rod with seed single crystal, it is implemented ingot dummy bar and implemented another silicon single crystals growth process.
EFFECT: higher parameters repeatability of grown ingots, and also reducing of growing of single crystals production cycle duration and energy saving at the expense of technological cycle optimisation.
SUBSTANCE: invention relates to growing high-temperature inorganic monocrystals and can be used in quantum electronics and elementary-particle physics, in particular for neutrinoless double beta decay detectors. The said monocrystals are grown by pulling zinc molybdate crystals ZnMoO4 from molten initial charge in a melting pot for inoculation. The initial charge used is a mixture of oxides ZnO and MoO3, taken in stoichiometric ratio with excess MoO3 in amount of 1.0-7.0 wt %, and growth takes place at crystallisation volume rate of over 0.4 cm3/h. Using Czochralski growth method, pulling rate is 0.3-3.0 mm/h with axial temperature gradient at the crystallisation front of 80-100°/cm. Using Kyropoulos growth method, pulling rate does not exceed 0.5 mm/h while maintaining crystal diametre of 80-95 % of the diametre of the melting pot.
EFFECT: proposed method allows for obtaining large monocrystals (size of 1 cm3 or more), with optical properties suitable for use as scintillation detectors and optical elements.
3 cl, 2 ex, 2 dwg
FIELD: mining engineering.
SUBSTANCE: invention relates to growing field from melt of polycrystalline silicon layer and can be used in manufacturing of solar cells (photo-transducer). Device for growing of layers 5 of silicon on carbonic substratum 4, switches on crucible, substratum, connected to its movement mechanism, capillary feeder and heater 2 of feeder, herewith capillary feeder and crucible are matched in one detail 1 in form of hollow boat with bottom slot, in which it is inserted element 3 made of carbonic capillary-porous material: carbonic thick felt or coal-graphitic fabric, contacting to substratum.
EFFECT: invention provides simplification and reduce the price of structure of thermal block and its control system, increasing of uniformity of thermal field in substratum field, and also consumption reduction of electricity and to reduce dimensions of growing vessel.
FIELD: crystal growing.
SUBSTANCE: crystal growing apparatus comprises double-section chamber, seed holder fixed on rod, crucible, furnace provided with heater assembled on U-shaped lamellas following the crucible outline, centering ring with closed parts of lamellas attached to it, and water-cooled annular current leads. According to invention, furnace is constructed in the form of two heaters similar in shape, mass, and size, which are mirror reflection of each other; closed parts of U-shaped lamellas are attached to centering ring being moved apart to 90°; rod with seed holder is disposed inside upper heater; free ends of lamellas are connected through conducting adapters to current leads with alternation of current charge signs as follows: "++--"; crucible is supported by insulated supports disposed between heater lamellas; conducting adapters are made from refractory material having resistivity lower than that of lamellas; and ends of adapters connected with lamellas are positioned at the same distance from axis of heater.
EFFECT: enabled growing large-size monocrystals and increased their structural perfection due to lack of supercooling of melt and increased service time of units.
6 cl, 2 dwg
FIELD: crystal growing.
SUBSTANCE: invention relates to technology of growing monocrystals seed crystal and can be used for growing monocrystals having different chemical composition, e.g., types A2B6 and A3B5, as well as monocrystals of refractory oxides, for instance sapphire. In a method preparing monocrystals by growing them from melt comprising melting starting material and drawing monocrystal by crystallization of melt on seed crystal at controlled removal of crystallization heat and use of independent heating sources forming own heat zones, according to invention, independent heating sources form two equal-sized coaxially disposed heat zones so that unified thermal melt and grown crystal region is created separated by melt mirror. Starting material is melted in two steps: first upper heat zone is heated by feeding upper heater with 50% power required to produce melt until maximum temperature providing stable state of seed crystal solid phase is attained, after which the rest of power is directed to lower heat zone onto lower heater at unchanged temperature of upper heat zone until batch is completely melted. Enlargement and growth of monocrystal proceed at controlled lowering of temperature in upper heat zone and preserved unchanged power fed into lower heat zone. Furthermore, crystallization heat is removed in crystal enlargement and growth step at a velocity calculated from following formula: g/sec, where Δm denotes crystal mass, g; Δτ denotes mass growth (Δm) time; Tmelt melting temperature of starting material, °C; Tcrit maximum temperature of stable state of seed crystal solid phase, °C; ΔT temperature change in upper heater in the process, °C; ΔHmelt specific melting point, cal/g; ρ pressure const; R crystal radius, cm; A = ΔT/ΔR is radial temperature gradient near crystallization zone, °C/cm; is initial axial temperature gradient in crystal growth zone, °C/cm; Cp specific heat capacity, cal/g-°C'; and λ heat conductivity of crystal, cal/cm-sec-°C.
EFFECT: achieved independence of process of grown monocrystal material, increased productivity, and increased structural perfection of monocrystal due to lack of supercooling in the course of growth.
FIELD: processes and devices for growing optical crystals designed for optic-electronic apparatuses.
SUBSTANCE: device includes housing with growing chamber and with cooling chamber mutually divided by means of ceramic partition, crucible arranged in growing chamber, induction heater, upper metallic heating shield mounted over crucible, mechanism with rod for moving crystal. Crucible is in the form of cylinder whose flat bottom is joined with cylindrical lateral surface along spherical surface. Metallic upper shield has two sections, lower cone section and upper spherical section. Between chamber for growing and chamber for cooling diaphragm with changeable concentric inserts is arranged. Induced Foucault current detector in the form of cylinder is mounted on bottom part of crucible. Inner diameter of any concentric insert of said diaphragm exceeds by 2 - 16 mm diameter of grown crystal. Concentric inserts of diaphragm are made of crucible material. Relation of height of cylindrical wall of crucible to height of wall of induced Foucault current detector is in range 2 - 10. Relation of height of cone section of upper metallic shield to height of spherical section of said shield is in range 2 - 5. Apparatus allows grow large-size (with diameter and length more than 100 mm) oxide crystals (LiNbO3, LiTaO3 and others) of high optical quality and excellent structure quality.
EFFECT: possibility for growing mono-crystals with improved optical properties and enhanced structure.