NUMERICAL STUDY OF THE INFLUENCE OF REACTOR DESIGN ON MOCVD WITH A COMPARISON TO EXPERIMENTAL-DATA

Comparisons were made between experimental data and a two-dimensional model for the MOCVD of GaAs from trimethylgallium and arsine in two horizontal air cooled reactor geometries. A unique feature of this work was that comparison was made, not only on the wafer, but over the entire deposition regime. Excellent agreement was achieved for growth at low system pressures. Experimental deposition profiles under atmospheric pressure were much less uniform than those predicted by the model. This difference could not be attributed to a pressure dependence of heterogeneous reactions. Inclusion of thermal diffusion had little effect on the uniformity of the calculated deposition profile but decreased the magnitude of the growth rate by up to 12%. Through model calculations and experiments, it was determined that a channel with a tilted susceptor. Substrate rotation was predicted to cause growth rate uniformity within less than 4.3% in horizontal channel flow and 3.8% in a channel with tilted walls.