A SiC single crystal comprising no polycrystals, and no cracking other than at the side edges is provided. A method for producing SiC single crystal in which seed crystal held at bottom end face of holding shaft is contacted with SiC solution having temperature gradient to grow SiC single crystal, wherein the contour of the end face of the holding shaft is smaller than the contour of the top face of the seed crystal, the top face of the seed crystal has center section held in contact with the entire surface of the end face of the holding shaft and outer peripheral section that is not in contact with the end face of the holding shaft, and carbon sheet is disposed on the top face of the seed crystal so as to cover at least the outer peripheral section, among the center section and the outer peripheral section.

Techniques for processing materials in supercritical fluids including processing in a capsule disposed within a high-pressure apparatus enclosure are disclosed. The disclosed techniques are useful for growing crystals of GaN, AlN, InN, and their alloys, including InGaN, AlGaN, and AlInGaN for the manufacture of bulk or patterned substrates, which in turn can be used to make optoelectronic devices, lasers, light emitting diodes, solar cells, photoelectrochemical water splitting and hydrogen generation devices, photodetectors, integrated circuits, and transistors.

A pressure differential can be applied across a mold sheet and a semiconductor (e.g. silicon) wafer (e.g. for solar cell) is formed thereon. Relaxation of the pressure differential can allow release of the wafer. The mold sheet may be cooler than the melt. Heat is extracted through the thickness of the forming wafer. The temperature of the solidifying body is substantially uniform across its width, resulting in low stresses and dislocation density and higher crystallographic quality. The mold sheet can allow flow of gas through it. The melt can be introduced to the sheet by: full area contact with the top of a melt; traversing a partial area contact of melt with the mold sheet, whether horizontal or vertical, or in between; and by dipping the mold into a melt. The grain size can be controlled by many means.

Provided is a method for producing SiC single crystals while maintaining a temperature gradient such that the temperature decreases from within an Si solution inside a graphite crucible toward the solution surface, with the SiC seed crystals that have contacted the solution surface serving as the starting point for crystal seed growth, wherein when the crystal growth surface of the SiC seed crystals, which serves as the starting point for SiC single crystal growth, contacts the solution surface, the height by which the solution rises to the side of the SiC seed crystals is within the range where the SiC single crystals that have grown from the crystal growth surface and the SiC single crystals that have grown from the side grow as one SiC single crystal unit. Also provided is a device for producing an SiC single crystal comprising a graphite crucible, a heating device for heating and melting base materials in the crucible to form a base material solution and maintaining a temperature gradient required for growth of SiC single crystal, a support rod which holds a SiC seed crystal at its bottom end, and a holding structure which maintains the holding by the support rod so that a height by which the solution rises to the side of the SiC seed crystal is within a range where the SiC single crystal that have grown from the crystal growth surface and the SiC single crystal that have grown from the side grow as one SiC single crystal unit.

An apparatus and method for growing nitride bulk single crystal, including an autoclave having a pre-growth zone and a growth zone. With control of the concentration of a saturated solution in a pre-growth chamber, the oversaturation reaction conditions for the overall process of growth of the nitride bulk single crystal can be regulated. By regulating the liquid level difference of the melt on an upper surface of a seed crystal, nucleation growth of N/Ga is preferentially performed on the surface of the seed crystal, which suppresses polycrystal formation at a gas-liquid interface and improves the growth rate of crystal and the utilization rate of raw materials.

An apparatus and method for growing nitride bulk single crystal, including an autoclave having a pre-growth zone and a growth zone. With control of the concentration of a saturated solution in a pre-growth chamber, the oversaturation reaction conditions for the overall process of growth of the nitride bulk single crystal can be regulated. By regulating the liquid level difference of the melt on an upper surface of a seed crystal, nucleation growth of N/Ga is preferentially performed on the surface of the seed crystal, which suppresses polycrystal formation at a gas-liquid interface and improves the growth rate of crystal and the utilization rate of raw materials.

A large Group III nitride crystal of high quality with few defects such as a distortion, a dislocation, and warping is produced by vapor phase epitaxy. A method for producing a Group III nitride crystal includes: a first Group III nitride crystal production process of producing a first Group III nitride crystal 1003 by liquid phase epitaxy; and a second Group III nitride crystal production process of producing a second Group III nitride crystal 1004 on the first crystal 1003 by vapor phase epitaxy. In the first Group III nitride crystal production process, the surfaces of seed crystals 1003a (preliminarily provided Group III nitride) are brought into contact with an alkali metal melt, a Group III element and nitrogen are cause to react with each other in a nitrogen-containing atmosphere in the alkali metal melt, and the Group III nitride crystals are bound together by growth of the Group III nitride crystals grown from the seed crystals 1003a to produce a first crystal 1003.

A method of manufacturing an SiC single crystal includes the steps of melting a raw material in a crucible (14) to produce an SIC solution (15); and bringing a crystal growth surface (24A) of an SiC seed crystal (24) into contact with the SiC solution to cause an SiC single crystal to grow on the crystal growth surface. The crystal structure of the SiC seed crystal is the 4H polytype. The off-angle of the crystal growth surface is not smaller than 1 and not larger than 4. The temperature of the SIC solution during growth of the SiC single crystal is not lower than 1650 C. and not higher than 1850 C. The temperature gradient in a portion of the SiC solution directly below the SiC seed crystal during growth of the SiC single crystal is higher than 0 C./cm and not higher than 19 C./cm.

A crystal preparation apparatus (100) and a crystal preparation method (700). The crystal preparation apparatus (100) comprises: a growth cavity (110), the growth cavity (110) being internally provided with at least one layer of plate assembly (111); and a heating assembly (120), used for heating the growth cavity (110). The crystal preparation method (700) comprises: placing a raw material in the growth cavity (110) (710), the growth cavity (110) being internally provided with at least one layer of plate assembly (111); heating the growth cavity (110) by means of the heating assembly (120) so as to melt the raw material into a melt (720); bonding a seed crystal (180) to a seed crystal holder (150) (730); lowering the seed crystal holder (150) to which the seed crystal (180) is bonded, so that the seed crystal (180) is in contact with the melt; and preparing a crystal on the basis of the seed crystal (180) and the melt (750).

A crystal preparation apparatus (100) and a crystal preparation method (700). The crystal preparation apparatus (100) comprises: a growth cavity (110), the growth cavity (110) being internally provided with at least one layer of plate assembly (111); and a heating assembly (120), used for heating the growth cavity (110). The crystal preparation method (700) comprises: placing a raw material in the growth cavity (110) (710), the growth cavity (110) being internally provided with at least one layer of plate assembly (111); heating the growth cavity (110) by means of the heating assembly (120) so as to melt the raw material into a melt (720); bonding a seed crystal (180) to a seed crystal holder (150) (730); lowering the seed crystal holder (150) to which the seed crystal (180) is bonded, so that the seed crystal (180) is in contact with the melt; and preparing a crystal on the basis of the seed crystal (180) and the melt (750).