BULK SINGLE CRYSTAL PRODUCTION FACILITY EMPLOYING SUPERCRITICAL AMMONIA

摘要

There is provided an apparatus comprising an autoclave 1 for preparing a supercritical solvent equipped with a convection control means 2 for establishing a convection flow, wherein the dissolution zone 13 where a feedstock 16 is located above the convection control means 2 and the crystallization zone where a seed 17 is located below the convection control means are formed. A convection flow rate of the supercritical solution between the dissolution zone 13 and the crystallization zone 14 is determined by the degree of opening of the convection control means 2 and the temperature difference between the dissolution zone 13 and crystallization zone 14. Accordingly, the supercritical solution, in which the nitride has a negative temperature coefficient of solubility is supplied from the dissolution zone 13 to the crystallization zone 14 in which a seed is located through the convection control means 2 so that nitride crystal is selectively grown on the seed by maintaining supersaturation of the supercritical solution with respect to the seed at the predetermined raised temperature. In the apparatus according to the present invention, the concentration of the supercritical solution is controlled below a certain level so as not to allow spontaneous crystallization, so that a nitride bulk single crystal can be obtained.