Abstract: A nitride single crystal is produced on a seed crystal substrate 5 in a melt containing a flux and a raw material of the single crystal in a growing vessel 1. The melt 2 in the growing vessel 1 has temperature gradient in a horizontal direction. In growing a nitride single crystal by flux method, adhesion of inferior crystals onto the single crystal is prevented and the film thickness of the single crystal is made constant.

Abstract: A method of producing a monocrystalline semiconductor material includes providing a starting material composed of the semiconductor material, transferring the starting material into a heating zone in which a melt composed of the semiconductor material is fed with the starting material, and lowering the melt from the heating zone and/or raising the heating zone such that, at a lower end portion of the melt, a solidification front forms along which the semiconductor material crystallizes in a desired structure, wherein the starting material composed of the semiconductor material is provided in liquid form and fed into the melt in liquid form.

Abstract: In a crystal preparing device, a crucible holds a mixed molten metal containing alkali metal and group III metal. A container has a container space contacting the mixed molten metal and holds a molten alkali metal between the container space and an outside of the container, the molten alkali metal contacting the container space. A gas supply device supplies nitrogen gas to the container space. A heating device heats the crucible to a crystal growth temperature. The crystal preparing device is provided so that a vapor pressure of the alkali metal which evaporates from the molten alkali metal is substantially equal to a vapor pressure of the alkali metal which evaporates from the mixed molten metal.

Abstract: A single crystal of semiconductor material is produced by a method of melting semiconductor material granules by means of a first induction heating coil on a dish with a run-off tube consisting of the semiconductor material, forming a melt of molten granules which extends from the run-off tube in the form of a melt neck and a melt waist to a phase boundary, delivering heat to the melt by means of a second induction heating coil which has an opening through which the melt neck passes, crystallizing the melt at the phase boundary, and delivering a cooling gas to the run-off tube and to the melt neck in order to control the axial position of an interface between the run-off tube and the melt neck.

Abstract: Systems and methods for crystal growth are provided. One method includes producing a lateral thermal profile in a furnace having a crucible therein containing a material for growing a crystal. The lateral thermal profile has three zones, wherein the first and third zones have temperatures above and below a melting point of the material, respectively, and the second zone has a plurality of temperatures with at least one temperature equal to the melting point of the material. The method further includes combining the lateral thermal profile with a vertical thermal gradient produced in the furnace, wherein the vertical thermal gradient causes a point in a bottom of the crucible located in the third zone to be the coldest point in the crucible. The method also includes transferring heat from the first and second zones to the third zone to produce a leading edge of the interface.

Abstract: This disclosure pertains to a process for making single crystal Group III nitride, particularly gallium nitride, at low pressure and temperature, in the region of the phase diagram of Group III nitride where Group III nitride is thermodynamically stable comprises a charge in the reaction vessel of (a) Group III nitride material as a source, (b) a barrier of solvent interposed between said source of Group III nitride and the deposition site, the solvent being prepared from the lithium nitride (Li3N) combined with barium fluoride (BaF2), or lithium nitride combined with barium fluoride and lithium fluoride (LiF) composition, heating the solvent to render it molten, dissolution of the source of GaN material in the molten solvent and following precipitation of GaN single crystals either self seeded or on the seed, maintaining conditions and then precipitating out.

Abstract: The present disclosure discloses rare earth metal halide scintillators compositions with reduced hygroscopicity. Compositions in specific implementations include three group of elements: Lanthanides, (La, Ce, Lu, Gd or V), elements in group 17 of the periodic table of elements (CI, Br and I) and elements of group 13 (B, AI, Ga, In, TI), and any combination of these elements. Examples of methods for making the compositions are also disclosed.

Abstract: The present disclosure discloses, in one arrangement, a scintillator material made of a metal halide with one or more additional group-13 elements. An example of such a compound is Ce:LaBr3 with thallium (Tl) added, either as a codopant or in a stoichiometric admixture and/or solid solution between LaBr3 and TlBr. In another arrangement, the above single crystalline iodide scintillator material can be made by first synthesizing a compound of the above composition and then forming a single crystal from the synthesized compound by, for example, the Vertical Gradient Freeze method. Applications of the scintillator materials include radiation detectors and their use in medical and security imaging.

Abstract: A high-quality polycrystalline bulk semiconductor having a large crystal grain size is produced by the casting method in which growth is regulated so as to proceed in the same plane direction, i.e., the {110}; plane or {112} plane is disclosed. The process, which is for producing a polycrystalline bulk semiconductor, comprises: a step in which a melt of a semiconductor selected among Si, Ge, and SiGe is held in a crucible; a step in which a bottom part of the crucible is cooled to give a temperature gradient and that part of the melt which is located directly on the crucible bottom is rapidly cooled in the beginning of growth to supercool the melt around the crucible bottom; a step in which the crucible is cooled to grow nuclei on the crucible bottom due to the supercooled state of the melt around the crucible bottom and thereby grow dendritic crystals along the crucible bottom; and a step in which a polycrystalline bulk of the semiconductor is then grown on the upper side of the dendritic crystals.

Abstract: Systems and methods of manufacturing wafers are disclosed using a low EPD crystal growth process and a wafer annealing process are provided resulting in III-V/GaAs wafers that provide higher device yields from the wafer. In one exemplary implementation, there is provided a method of manufacturing a group III based material with a low etch pit density (EPD). Moreover, the method includes forming polycrystalline group III based compounds, and performing vertical gradient freeze crystal growth using the polycrystalline group III based compounds. Other exemplary implementations may include controlling temperature gradient(s) during formation of the group III based crystal to provide very low etch pit density.

Abstract: A process is disclosed for producing a doped gallium arsenide single crystal by melting a gallium arsenide starting material and subsequently solidifying the gallium arsenide melt, wherein the gallium arsenide melt contains an excess of gallium relative to the stoichiometric composition, and wherein it is provided for a boron concentration of at least 5×1017 cm?3 in the melt or in the obtained crystal. The thus obtained crystal is characterized by a unique combination of low dislocation density, high conductivity and yet excellent, very low optic absorption, particularly in the range of the near infrared.

Abstract: Bulk single crystal of aluminum nitride (AlN) having an a real planar defect density?100 cm?2. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.

Abstract: A directional solidification furnace includes a crucible for holding molten silicon and a lid covering the crucible and forming an enclosure over the molten silicon. The crucible also includes an inlet in the lid for introducing inert gas above the molten silicon to inhibit contamination of the molten silicon.

Abstract: Systems and methods are disclosed for crystal growth using VGF and VB growth processes to reduce body lineage. In one exemplary embodiment, there is provided a method of inserting an ampoule with raw material into a furnace having a heating source, growing a crystal using a vertical gradient freeze process wherein the crystallizing temperature gradient is moved relative to the crystal and/or furnace to melt the raw material and reform it as a monocrystalline compound, and growing the crystal using a vertical Bridgman process on the wherein the ampoule/heating source are moved relative each other to continue to melt the raw material and reform it as a monocrystalline compound.

Abstract: A method for purifying silicon bearing materials for photovoltaic applications includes providing metallurgical silicon into a crucible apparatus. The metallurgical silicon is subjected to at least a thermal process to cause the metallurgical silicon to change in state from a first state to a second state, the second stage being a molten state not exceeding 1500 Degrees Celsius. At least a first portion of impurities is caused to be removed from the metallurgical silicon in the molten state. The molten metallurgical silicon is cooled from a lower region to an upper region to cause the lower region to solidify while a second portion of impurities segregate and accumulate in a liquid state region. The liquid state region is solidified to form a resulting silicon structure having a purified region and an impurity region. The purified region is characterized by a purity of greater than 99.9999%.

Abstract: A method of forming a templated casting involves incorporating a liquid feedstock into the channels of a honeycomb substrate to form a feedstock-laden substrate, and directionally solidifying the liquid feedstock within the channels.

Abstract: A method and a device for producing oriented solidified blocks made of semi-conductor material are provided. The device includes a crucible, in which melt is received, and has an insulation which surrounds the crucible at least from the top and from the side and which is arranged at a distance therefrom at least above the crucible, and at least one heating device which is arranged above the crucible. The region inside the insulation above the crucible is divided by an intermediate cover in a process chamber and a heating chamber is arranged thereabove, where at least one heating element is arranged.

Abstract: An apparatus and process are provided for directional solidification of silicon by electric induction susceptor heating in a controlled environment. A susceptor vessel is positioned between upper and lower susceptor induction heating systems and a surrounding induction coil system in the controlled environment. Alternating current selectively applied to induction coils associated with the upper and lower susceptor heating systems, and the induction coils making up the surrounding induction coil system, result in melting of the silicon charge in the vessel and subsequent directional solidification of the molten silicon. A fluid medium can be directed from below the vessel towards the bottom, and then up the exterior sides of the vessel to enhance the directional solidification process.

Abstract: Systems and methods are disclosed for crystal growth using VGF and VB growth processes to reduce body lineage. In one exemplary embodiment, there is provided a method of inserting an ampoule with raw material into a furnace having a heating source, growing a crystal using a vertical gradient freeze process wherein the crystallizing temperature gradient is moved relative to the crystal and/or furnace to melt the raw material and reform it as a monocrystalline compound, and growing the crystal using a vertical Bridgman process on the wherein the ampoule/heating source are moved relative each other to continue to melt the raw material and reform it as a monocrystalline compound.

Abstract: It is disclosed an apparatus for growing a nitride single crystal using a flux containing an easily oxidizable substance. The apparatus has a crucible for storing the flux; a pressure vessel for storing the crucible and charging an atmosphere containing at least nitrogen gas; furnace materials disposed within the pressure vessel and out of the crucible; heaters attached to the furnace material; and alkali-resistant and heat-resistant metallic layers covering the furnace material.

Abstract: A wafer slicing method includes winding a wire around rollers and pressing the wire against an ingot while supplying slurry to the rollers. A previously conducted experiment provides a supply temperature profile of the slurry during the slicing process and the relationship to the axial displacement of the rollers. This relationship is used to implement slurry delivery during the slicing process. The resultant wafers are bowed in a uniform direction. This slicing method provides excellent reproducibility in addition to producing wafers that are bowed in a uniform direction.

Abstract: The present invention is a method for producing a single crystal that is a multi-pulling method for pulling a plurality of single crystals from a raw material melt in a same crucible in a chamber by a Czochralski method, comprising steps of: pulling a single crystal from a raw material melt ; then additionally charging polycrystalline raw material in a residual raw material melt without turning off power of a heater, and melting the polycrystalline raw material; then pulling a next single crystal; and repeating the steps and thereby pulling the plurality of single crystals.

Abstract: Disclosed herein is an apparatus for manufacturing a polycrystalline silicon ingot for solar batteries having a door control device using a hinge. The apparatus includes a vacuum chamber, a crucible, a susceptor which surrounds the crucible, a heater which heats the crucible, and an insulation plate which is disposed below the susceptor and has an opening therein. The apparatus further includes a cooling plate which moves upwards through the opening of the insulation plate and comes into close contact with or approaches the lower end of the susceptor, a cooling plate moving unit which actuates the cooling plate, a temperature sensor which measures the temperature of the crucible, and a control unit which controls the temperature in the crucible and the cooling plate moving unit. Furthermore, a door is provided on the insulation plate to open or close the opening of the insulation plate. The hinge is provided between the door and the insulation plate.

Abstract: A compositionally graded material having low defect densities and improved electronic properties is disclosed and described. A compositionally graded inorganic crystalline material can be formed by preparing a crystalline substrate by forming crystallographically oriented pits across an exposed surface of the substrate. A transition region can be deposited on the substrate under substantially epitaxial growth conditions. Single crystal substrates of a wide variety of materials such as diamond, aluminum nitride, silicon carbide, etc. can be formed having relatively low defect rates.

Abstract: A method for producing growth-axis oriented single crystal sapphire cores or near-net cores is provided. According to the method, a boule is grown on a desired growth axis having a first axial end and a second axial end. An orientation of a plane normal to the desired growth axis with respect to the boule is determined. The boule is then cored in a direction perpendicular to the plane to produce at least one growth-axis oriented single crystal sapphire core, or the boule is outer-diameter-grinded the boule to form a single crystal sapphire near-net core.

Abstract: A method for producing a p-type SiC semiconductor single crystal, including: using a solution in which C is dissolved in a Si melt and 30 to 70 at. % Cr and 0.1 to 20 at. % Al, based on a total weight of the Si melt, Cr, and Al, are added to the Si melt, to grow a p-type SiC semiconductor single crystal on a SiC single crystal substrate from the solution.

Abstract: Silicon raw material is filled into a graphite crucible (10), the graphite crucible (10) is heated to form molten silicon (M), at least one rare earth element and at least one of Sn, Al, and Ge are added to molten silicon (M), and a temperature gradient is maintained in the molten silicon in which the temperature decreases from within the molten silicon toward the surface while growing an silicon carbide single crystal starting from an silicon carbide seed crystal (14) held immediately below the surface of the molten liquid.

Abstract: Methods and apparatuses are provided for casting silicon for photovoltaic cells and other applications. With such methods and apparatuses, a cast body of monocrystalline silicon may be formed that is free of, or substantially free of, radially-distributed impurities and defects and having at least two dimensions that are each at least about 35 cm is provided.

Abstract: A crystal growth apparatus comprises a reaction vessel holding a melt mixture containing an alkali metal and a group III metal, a gas supplying apparatus supplying a nitrogen source gas to a vessel space exposed to the melt mixture inside the reaction vessel, a heating unit heating the melt mixture to a crystal growth temperature, and a support unit supporting a seed crystal of a group III nitride crystal inside the melt mixture.

Abstract: Systems and methods of manufacturing wafers are disclosed using a low EPD crystal growth process and a wafer annealing process are provided resulting in III-V/GaAs wafers that provide higher device yields from the wafer. In one exemplary implementation, there is provided a method of manufacturing a group III based material with a low etch pit density (EPD). Moreover, the method includes forming polycrystalline group III based compounds, and performing vertical gradient freeze crystal growth using the polycrystalline group III based compounds. Other exemplary implementations may include controlling temperature gradient(s) during formation of the group III based crystal to provide very low etch pit density.

Abstract: A method for locally controlling the stoichiometry of an epitaxially deposited layer on a semiconductor substrate is provided. The method includes directing a first reactant gas and a doping gas across a top surface of a semiconductor substrate and directing a drive gas and a second reactant gas against the substrate separately from the first reactant gas in a manner that rotates the substrate while introducing the second reactant gas at an edge of the substrate to control each reactant separately, thereby compensating and controlling depletion effects and improving doping uniformity in resulting epitaxial layers on the substrate.

Abstract: A seed crystal is immersed in a melt containing a flux and a single crystal material in a growth vessel to produce a nitride single crystal on the seed crystal. A difference (TS-TB) of temperatures at a gas-liquid interface of the melt (TS) and at the lowermost part of the melt (TB) is set to 1° C. or larger and 8° C. or lower. Preferably, the substrate of seed crystal is vertically placed.

Abstract: A method for eliminating precipitates contained in an II-VI solid semiconductor material, in which the solid semiconductor material is a congruent sublimation solid semiconductor material, the method including: providing an inert gas flow; heating the solid semiconductor material under the inert gas flow up to a temperature T, between a first temperature T1, corresponding to compound II-VI/element VI eutectic, and a second temperature T2, corresponding to maximum congruent sublimation temperature; maintaining the solid semiconductor material at this temperature T under a neutral gas flow for a time period sufficient to eliminate the precipitates; cooling the solid semiconductor material under the inert gas flow from temperature T to ambient temperature, at a rate such that, during the cooling, the solid semiconductor material merges with its congruent sublimation line; and recovering a precipitate-free solid semiconductor material.

Abstract: In a method of growing single crystals from melt, the starting material is fused and a single crystal is pulled by crystallization of the melt on a seed crystal with controlled removal of the crystallization heat. Independent heating sources constituting thermal zones are used and constitute two equal-sized coaxial thermal zones which make up a united thermal area for the melt and the single crystal being grown and are separated by the melt starting material being carried out by heating the upper thermal zone with a heater 30-50% of power required for obtaining the melt, until in the upper thermal zone maximum temperature is reached The remaining power is supplied to the lower thermal zone to a lower heater with maintaining constant temperature of the upper thermal zone till complete melting of the charge. Single crystal enlargement and growing is conducted with controlled lowering of temperature in the upper thermal zone.

Abstract: Techniques for the formation of a silicon ingot using a low-grade silicon feedstock include forming within a crucible device a molten silicon from a low-grade silicon feedstock and performing a directional solidification of the molten silicon to form a silicon ingot within the crucible device. The directional solidification forms a generally solidified quantity of silicon and a generally molten quantity of silicon. The method and system include removing from the crucible device at least a portion of the generally molten quantity of silicon while retaining within the crucible device the generally solidified quantity of silicon. Controlling the directional solidification of the generally solidified quantity of silicon, while removing the more contaminated molten silicon, results in a silicon ingot possessing a generally higher grade of silicon than the low-grade silicon feedstock.

Abstract: To reduce the heat input to the bottom of the crucible and to control heat extraction independently of heat input, a shield can be raised between a heating element and a crucible at a controlled speed as the crystal grows. Other steps could include moving the crucible, but this process can avoid having to move the crucible. A temperature gradient is produced by shielding only a portion of the heating element; for example, the bottom portion of a cylindrical element can be shielded to cause heat transfer to be less in the bottom of the crucible than at the top, thereby causing a stabilizing temperature gradient in the crucible.

Abstract: The process for growing a rare earth aluminum or gallium garnet crystal from a melt includes melting an aluminum or gallium garnet of at least one rare earth, preferably Lu or Y, or a mixture of oxides of formula Me2O3, wherein Me represents the rare earth or aluminum or gallium. The melt also includes a fluoride anion acting as a counter ion for the rare earth and the aluminum or gallium. The components comprising the rare earth and aluminum or gallium are introduced in the melt so that the amounts of the rare earth and aluminum or gallium are defined by the formula: SE(3-x)X(5-y)O(12-2x-2y)F(x+y), wherein 0?x?0.2 and 0?y?0.2 and 0<x+y?0.4, and X is aluminum or gallium. The resulting crystals are used for optical elements at 193 nm, such as lenses, and as scintillation materials.

Abstract: A method of manufacturing group III-nitride semiconductor crystal includes the steps of accommodating an alloy containing at least a group III-metal element and an alkali metal element in a reactor, introducing a nitrogen-containing substance in the reactor, dissolving the nitrogen-containing substance in an alloy melt in which the alloy has been melted, and growing group III-nitride semiconductor crystal is provided. The group III-nitride semiconductor crystal attaining a small absorption coefficient and an efficient method of manufacturing the same, as well as a group III-nitride semiconductor device attaining high light emission intensity can thus be provided.

Abstract: The method of making a single crystal, especially a CaF2 single crystal, includes tempering, in which the crystal is heated at <18 K/h to a temperature of 1000° C. to 1350° C. and held at this temperature for at least 65 hours with maximum temperature differences within the crystal of <0.2 K. Subsequently the crystal is cooled with a cooling rate of at maximum 0.5 K/h above a limiting temperature between 900° C. to 600° C. and then further below this limiting temperature at maximum 3 K/h. The obtained CaF2 crystals have refractive index uniformity <0.025×10?6 (RMS) in a (111)-, (100)- or (110)-direction and a stress birefringence of less than 2.5 nm/cm (PV) and/or a stress birefringence of less than 1 nm/cm (RMS) in the (100)- or (110)-direction. In the (111)-direction the stress birefringence is <0.5 nm/cm (PV) and/or the stress birefringence is <0.15 nm/cm (RMS).

Abstract: A process for obtaining bulk mono-crystalline gallium-containing nitride, liminating impurities from the obtained crystal and manufacturing substrates made of bulk mono-crystalline gallium-containing nitride has been now proposed.

Abstract: A method for producing a crystallographically-oriented ceramic includes the steps of forming a first sheet with a thickness of 10 ?m or less containing a first inorganic material in which grain growth occurs at a first temperature or higher and a second sheet containing a second inorganic material in which grain growth occurs at a second temperature higher than the first temperature, laminating one or more each of the first and second sheets to form a laminated body, firing the laminated body at a temperature equal to or higher than the first temperature and lower than the second temperature to cause grain growth in the first inorganic material, and then firing the laminated body at a temperature equal to or higher than the second temperature to cause grain growth in the second inorganic material in the direction of a crystal plane of the first inorganic material.

Abstract: Provided are a crucible which prevents polycrystal formation to easily allow growth of optical part material single crystals, and a single crystal growth method employing the crucible. The crucible has a smooth surface of about Rmax 3.2 s as the surface roughness of the wall surface 1H, concave curved plane 1J, cone surface 1F and convex curved plane 1L of the starting material carrying section 1D and the wall surface 1K of the seed carrying section 1E, which constitute the inner surface of the crucible of a crucible body 1A.

Abstract: A process for manufacturing a wafer of a silicon carbide single crystal having: cutting a wafer from an ? (hexagonal)-silicon carbide single crystal so that the off-angle is totally in the range from 0.4 to 2° to a plane obtained in perpendicular to the [0001]c axis of the silicon carbide single crystal; disposing the wafer in a reaction vessel; feeding a silicon source gas and carbon source gas in the reaction vessel; and epitaxially growing the ? (hexagonal) silicon carbide single crystal on the wafer by allowing the silicon source gas and carbon source gas to react.

Abstract: A molding assembly for forming an ingot, including side members each having engaging end portions, the engaging end portions of the side members being engaged with respective ones of the side members such that the side members form a polygonal prism having sides, corners, a top opening and a bottom opening, the engaging end portions of the side members engaging to form connecting portions positioned in the sides, and a bottom member fitted to close the bottom opening of the polygonal prism so as to form a molding device for molding a molten material into an ingot.

Abstract: A method and apparatus for producing bulk single crystals of AlN having low dislocation densities of about 10,000 cm?2 or less includes a crystal growth enclosure with Al and N2 source material therein, capable of forming bulk crystals. The apparatus maintains the N2 partial pressure at greater than stoichiometric pressure relative to the Al within the crystal growth enclosure, while maintaining the total vapor pressure in the crystal growth enclosure at super-atmospheric pressure. At least one nucleation site is provided in the crystal growth enclosure, and provision is made for cooling the nucleation site relative to other locations in the crystal growth enclosure. The Al and N2 vapor is then deposited to grow single crystalline low dislocation density AlN at the nucleation site. High efficiency ultraviolet light emitting diodes and ultraviolet laser diodes are fabricated on low defect density AlN substrates, which are cut from the low dislocation density AlN crystals.

Abstract: Methods and apparatuses are provided for casting silicon for photovoltaic cells and other applications. With these methods, an ingot can be grown that is low in carbon and whose crystal growth is controlled to increase the cross-sectional area of seeded material during casting.

Abstract: A method of manufacturing calcium fluoride single crystal includes cooling the calcium fluoride single crystal with variable cooling rates so that throughout a temperature range in the cooling step, maximum shear stress inside the calcium fluoride single crystal caused by thermal stress is approximately equal to or smaller than critical resolved shear stress (?c) of the calcium fluoride single crystal in a <1 1 0> direction on a {0 0 1} plane of the calcium fluoride single crystal, and is maintained to be an approximately constant ratio, and adding strontium fluoride when growing the single crystal before the cooling step.

Abstract: It is to provide a substrate for growing a semiconductor, which is effective for suppressing an occurrence of surface defects different in type from hillock defects in case of epitaxially growing a compound semiconductor layer, particularly an Al-based compound semiconductor layer. In a substrate for growing a compound semiconductor, in which a crystal surface inclined at a predetermined off angle with respect to a (100) plane is a principal plane, an angle made by a direction of a vector obtained by projecting a normal vector of the principal plane on the (100) plane and one direction of a [0-11] direction, a [01-1] direction, a [011] direction and a [0-1-1] direction is set to be less than 35°, and the compound semiconductor layer is epitaxially grown on the substrate.

Abstract: A method is provided for preparing, with high reproducibility, a carbon-doped group III-V compound semiconductor crystal having favorable electrical characteristics and having impurities removed therefrom, and in which the amount of doped carbon can be adjusted easily during crystal growth. This method includes the steps of: filling a crucible with compound raw material, solid carbon, and boron oxide; sealing the filled crucible gas impermeable material; heating and melting the compound raw material under the sealed state in the airtight vessel; and solidifying the melted compound raw material to grow a carbon-doped compound semiconductor crystal.

Abstract: A method of preparing a compound semiconductor crystal is able to dope the crystal with carbon with high reproducibility. The method includes the steps of sealing a carbon oxide gas of a predetermined partial pressure and a compound semiconductor material in a gas-impermeable airtight vessel, increasing the temperature of the vessel to melt the compound semiconductor material sealed in the vessel, and then decreasing the temperature of the vessel to solidify the melted compound semiconductor material to grow a compound semiconductor crystal containing a predetermined amount of carbon. With this method, a compound semiconductor crystal with a carbon concentration of 0.1×1015cm?3 to 20×1015cm?3 is prepared with high reproducibility.