Liquid encapsulation method for growing single semiconductor crystals

Abstract

A liquid encapsulation Czockralski method for growing a single crystal of a semiconductor compound which comprises: melting a semiconductor compound in the presence of a B.sub.2 O.sub.3 liquid encapsulant to form a two phase liquid; dipping a semiconductor seed crystal into the compound melt covered with the B.sub.2 O.sub.3 encapsulant; growing the crystal from the compound melt by pulling up and rotating the seed crystal; and, cooling the crystal in a cooling zone above a crucible. The cooling zone is maintained at a substantially uniform temperature distribution with a small temperature gradient by using primarily an independently controlled crystal cooling zone heater H3. In addition, an independently controlled melt heater H1 and an independently controlled crystal growing heater H2 are employed. Also, a crystal cooling zone heat shield 11 can be provided to aid in slowly cooling the grown crystal in the substantially uniform temperature distribution. Preferably, a crystal cooling zone heater H3 is employed to control the temperature distribution in the cooling zone. The semiconductor crystals produced by employing the process and apparatus of the invention are substantially crack-free both before and after grinding and cutting. Also the etch pitch density (EPD) of the semiconductor crystal material is significantly lower than conventionally produced material.