SEED CRYSTAL FOR PRODUCING NON-DISLOCATION GAAS SINGLE CRYSTAL

摘要

PURPOSE:To obviate deterioration in melting of a seed crystal and deposition of a polycrystal to the front end of the seed crystal even if the temp. of a raw material melt deviates slightly from the m.p. and to prevent generation of a propagation-dislocation by providing an In concn. gradient to the seed crystal at the time of producing the non-dislocation Ga As single crystal added with In by an LEC method. CONSTITUTION:The concn. gradient of In is provided as follows to the seed crystal 1 for producing the non-dislocation Ga-As single crystal add with In by the LEC method: The concn. of the In at the end part is so set that the m.p. at the end part of the seed crystal first coming into contact with the raw material melt 4 is slightly lower then the temp. on the surface 3 of the raw material melt, then the concn. of the In is so set as to be lowered toward the other end part of the seed crystal. The concn. of the In at the bottom end of the seed crystal 1 is preferably set at the value obtd. by multiplying the concn. of the In of the raw material melt by a segrefaction coefft. or larger.