GaAs single crystal for 3 inch diameter wafers grown by horizontal zone melt technique

Abstract

We have developed a new horizontal zone melter (HZM) for boat growth of 3 inch diameter GaAs wafers. A silicon carbide (SiC) ring heater was used in the GaAs melting zone to concentrate the heating power in the small zone, and to minimize the variation in the longitudinal carrier concentration in the crystal. In order to maintain a flat, or a slightly convex, solid-liquid interface in the direction of crystal growth, the axial temperature gradient of the GaAs melt was minimized and the melt convection currents were reduced only in a small part of the GaAs melt near the solid-liquid interface. A Si-doped GaAs single crystal some 10 kg in weight and 600 mm in length was grown with the HZM. The length of the melting zone was 200 mm long. The longitudinal carrier concentration was constant from the seed (g = 0.1) to the middle (g = 0.65). The average dislocation densities of the 3 inch diameter wafers were about 2000 cm -2 both from near the seed and the tail.