Patent ID: 7335262
Filing Date: 2008-02-26
Classification: C30B,Y10T

Abstract:
1. An apparatus for obtaining a bulk single crystal comprising an autoclave for preparing a supercritical solvent equipped with a convection control means for establishing a convection flow, and mounted inside a furnace unit equipped with a heating device and a cooling device, wherein the furnace unit is controlled to obtain a temperature gradient within said autoclave by said heating device and/or cooling device, wherein the convection control means comprises at least one horizontal baffle having a central opening and/or a space between the baffle and an inner wall of the autoclave, and separating the dissolution zone where a feedstock is located above said baffle from said crystallization zone where a seed is located below said baffle, wherein nitride is dissolved in the supercritical solvent containing ammonia and at least alkali metal ions to make the supercritical solution, in which the nitride has a negative temperature coefficient of solubility and the supercritical solution is supplied from said dissolution zone to said crystallization zone in which a seed is located through said convection control means so that nitride crystal is grown on the seed arranged in the autoclave, wherein a lining of metal such as Ag, Mo, Fe or Ta, or alloy thereof is applied to an inner wall of the autoclave.