METHOD AND APPARATUS OF GROWING LOW-DISLOCATION DENSITY SINGLE CRYSTAL

PURPOSE:To obtain a low-dislocation density crystal by providing auxiliary heaters in addition to a main heater in pulling and growing a single crystal, controlling the temp. at the part close to the contact part of a melt surface with a crucible, and minimizing the thermal stress applied to the crystal at the growing time. CONSTITUTION:In a growing apparatus for a single crystal having low dislocation density such as GaAs, auxiliary heaters 7, 8 in addition to a heater 1 are provided to a crucible 2. The auxiliary heater 7 is arranged at the position of a melt surface and the temp. is controlled by a thermocouple 7' or the like. The side face of a crystal 4 after growing is heated by the auxiliary heater 8 so as to lower a thermal stress by making the temp. at the inside of the crystal 4 uniform. In this manner, the control of the diameter a crystal having low-dislocation density becomes easy.