INFLUENCE OF CRUCIBLE SUPPORT AND RADIAL HEATING ON THE INTERFACE SHAPE DURING VERTICAL BRIDGMAN GAAS GROWTH

Crucible assembly in a vertical Bridgman furnace is investigated by a numerical finite element model with the aim to obtain convex interface s during the growth of GaAs crystals. During the growth stage of the c onic section, a new funnel shaped crucible support has been found more effective than the concentric cylinders design similar to that patent ed by AT&T in promoting interface convexity. For the growth stages of the constant diameter section, the furnace profile can be effectively modulated by localized radial heating at the gradient zone. With these two features being introduced into a new furnace design, it is shown numerically that enhancement of interface convexity can be achieved us ing the presently available crucible materials.