SYNTHESIZING METHOD FOR CUBIC BORON NITRIDE SINGLE CRYSTAL

摘要

PURPOSE:To form a large crystal of curbic boron nitride by treating raw material boron nitride and a specific solvent substance under the pressure and temperature in which cubic boron nitride is stabilized and at the temperature of melting point of solvent substance or higher in the presence of cubic boron nitride seed crystals. CONSTITUTION:Raw material boron nitride and a solvent substance are caused to exist together in the presence of cubic boron nitride seed crystals, and cubic boron nitride is synthesized under the pressure and temperature in which cubic boron nitride is stabilized and at the temperature of melting point of solvent substance or higher. At that time, as the solvent substance, a mixture of one kind or more of borate of alkali metal and borate of alkaline earth metal, one kind or more of Li3N and Li3BN2 and one kind or more of Ca3N2 and Ca3B2N4 is used. The suitable ratio is 1-10wt.% of one kind or more of Li3N and Li3BN$2, 3-30wt.% of one kind or more of Ca3N2 and Ca3B2N4 and one kind or more of borate of alkali metal borate of alkaline earth metal for the remaining portion.