B2O3 MATERIAL FOR COATING SURFACE OF WALL OF CRUCIBLE, ITS PRODUCTION, PRODUCTION OF SINGLE CRYSTAL USING SAME AND SINGLE CRYSTAL PRODUCED BY SAID PRODUCTION

摘要

PROBLEM TO BE SOLVED: To suppress the defective coating of the diameter increasing part of a crucible and to obtain a single crystal in a high yield by disposing a B2O3 material on the bottom of the crucible and melting it by heating to coat the surface of the wall of the crucible. SOLUTION: A hollow conical B2O3 material 5 is disposed so that it adheres to the lower tapering part 10 of a crucible 1. Preferably a polycrystalline material 4 such as GaAs, GaP, InP or ZnSe is tightly filled into the conical hollow part so as to surely coat the tapering part 10 with B2O3 when the B2O3 material 5 melts. A truncated conical polycrystalline material 4 is most preferably used. A vertical boat method is adopted as a crystal growth method and a crystal is grown, e.g. by a VB method by which a crystal is solidified by varying the relative position of the crucible 1 and a furnace while keeping a constant temperature gradient or a VGF method by which a crystal is solidified by controlling the temperature of a heater while fixing the furnace.