Constitutional Supercooling during the Crystal Growth of Germanium and Silicon

Growth of heavily doped germanium and silicon crystals is investigated from the standpoint of constitutional supercooling. When the impurity concentration exceeds a certain value, corrugations appear on the crystal surface. The impurity concentration necessary for the appearance of the corrugation, the doping limit, is determined for various impurity elements. The analysis of the experimental results shows that definite magnitude of supercooling is required for the irregular growth of crystals which gives rise to corrugations on the crystal surface and results in the formation of polycrystals.