A SiC single crystal having high crystallinity and a large diameter is provided. A SiC single crystal comprising a seed crystal with a c-plane and a non-c-plane, and a c-plane growth portion and an enlarged diameter portion that have grown from the c-plane and the non-c-plane of the seed crystal as origins in the direction of the c-plane and the direction of the non-c-plane, wherein a continuous region free of threading dislocations is present in a peripheral portion of a plane that is parallel to the c-plane of the seed crystal, and contains the seed crystal and the enlarged diameter portion, wherein the area of the continuous region occupies 50% or more of the total area of the plane.

A SiC single crystal having high crystallinity and a large diameter is provided. A SiC single crystal comprising a seed crystal with a c-plane and a non-c-plane, and a c-plane growth portion and an enlarged diameter portion that have grown from the c-plane and the non-c-plane of the seed crystal as origins in the direction of the c-plane and the direction of the non-c-plane, wherein a continuous region free of threading dislocations is present in a peripheral portion of a plane that is parallel to the c-plane of the seed crystal, and contains the seed crystal and the enlarged diameter portion, wherein the area of the continuous region occupies 50% or more of the total area of the plane.

The present invention relates to a silicon-based molten composition for forming a SiC single crystal by a solution method, the composition containing silicon, carbon, and a metal satisfying 0.70Csisol1.510 with respect to a solubility parameter (Csisol) defined by the following Equation (1):

Csisol=AB+12Equation (1) wherein, A is first energy (A) of a first evaluation lattice containing silicon atoms, carbon atoms, and metal atoms, in a silicon crystal lattice containing the metal and the carbon; B is second energy (B) of a second evaluation lattice containing silicon atoms and metal atoms, in a silicon crystal lattice containing the metal; 1 is 5.422 as a constant value, and 2 is 9.097 as a constant value.

A monolithic crystal having the atomic formula W.sub.nX.sub.mY.sub.pZ.sub.r, with at least one dimension greater than about 10 mm. A method for top seed, solution growth of a monolithic crystal, wherein the method includes the steps of: preparing a precursor, forming a seed crystal, and forming the monolithic crystal. Some configurations of the method include the differential control of the crystal flux temperature in a furnace and the rotational frequency of a seed crystal in the crystal flux.

A monolithic crystal having the atomic formula W.sub.nX.sub.mY.sub.pZ.sub.r, with at least one dimension greater than about 10 mm. A method for top seed, solution growth of a monolithic crystal, wherein the method includes the steps of: preparing a precursor, forming a seed crystal, and forming the monolithic crystal. Some configurations of the method include the differential control of the crystal flux temperature in a furnace and the rotational frequency of a seed crystal in the crystal flux.

It is used a crucible containing a flux and a source material, a reaction vessel containing the crucible, an intermediate vessel containing the reaction vessel, and a pressure vessel containing the intermediate vessel and used to fill a gas comprising at least a nitrogen atom. When the flux and the source material are melted by heating to grow the nitride crystal, a vapor of an organic compound is provided in a space outside of the reaction vessel and inside of the intermediate vessel.

It is used a crucible containing a flux and a source material, a reaction vessel containing the crucible, an intermediate vessel containing the reaction vessel, and a pressure vessel containing the intermediate vessel and used to fill a gas comprising at least a nitrogen atom. When the flux and the source material are melted by heating to grow the nitride crystal, a vapor of an organic compound is provided in a space outside of the reaction vessel and inside of the intermediate vessel.

An oxychloride infrared nonlinear optical crystal and the preparation method and use thereof, the optical crystal has a general chemical formula of Pb.sub.2+xOCl.sub.2+2x, therein 0<x<0.139 or 0.141<x<0.159 or 0.161<x0.6. The crystal is non-centrosymmetric, belongs to orthonormal system with space group of Fmm2, cell parameter is a=35.4963(14)0.05 , b=5.8320(2)0.05 , c=16.0912(6)0.05 . The crystal is prepared by high temperature melt method or flux method. The crystal has a strong second harmonic generation efficiency of 4 times that of KDP (KH.sub.2PO.sub.4) tested by Kurtz method, it is phase machable, transparent in the range of 0.34-7 m. The laser damage threshold is 10 times that of the current commercial infrared nonlinear optical crystal AgGaS.sub.2. No crystalline water exists in lead oxychloride, and it is stable in the air and has good thermal stability.

An oxychloride infrared nonlinear optical crystal and the preparation method and use thereof, the optical crystal has a general chemical formula of Pb.sub.2+xOCl.sub.2+2x, therein 0<x<0.139 or 0.141<x<0.159 or 0.161<x0.6. The crystal is non-centrosymmetric, belongs to orthonormal system with space group of Fmm2, cell parameter is a=35.4963(14)0.05 , b=5.8320(2)0.05 , c=16.0912(6)0.05 . The crystal is prepared by high temperature melt method or flux method. The crystal has a strong second harmonic generation efficiency of 4 times that of KDP (KH.sub.2PO.sub.4) tested by Kurtz method, it is phase machable, transparent in the range of 0.34-7 m. The laser damage threshold is 10 times that of the current commercial infrared nonlinear optical crystal AgGaS.sub.2. No crystalline water exists in lead oxychloride, and it is stable in the air and has good thermal stability.

A method for producing a SiC single crystal by a solution method of bringing a seed crystal into contact with a Si solution of C and pulling up a SiC single crystal, the production method of a SiC single crystal including connecting the seed crystal to a seed crystal holder, disposing a cooling mechanism on the seed crystal holder, and promoting cooling of the seed crystal holder by the cooling mechanism in accordance with an increase in the pulling amount of the SiC single crystal.