GROWTH PRESSURE-DEPENDENCE OF SELECTIVE-AREA METALORGANIC VAPOR-PHASEEPITAXY ON PLANAR PATTERNED SUBSTRATES

We investigated the growth mechanism of selective area metalorganic va por phase epitaxy (MOVPE) on planar mask-patterned substrates by analy zing the growth pressure dependence of the in-plane growth rate distri bution using an equation we reported previously [T. Fujii, M. Ekawa an d S. Yamazaki, J. Crystal Growth 146 (1995) 475]. Experiments showed t hat the lateral diffusion constants defined at the epilayer and mask s urfaces are inversely proportional to growth pressure. This dependence is evidence of negligible surface migration both on the epilayer and mask surfaces. The growth rate enhancement produced by mask patterning increased and saturated as growth pressure increased. Our theory pred icts, however, that enhancement is proportional to growth pressure whe n the growing probability on the mask surface is exactly zero, This co ntradiction suggests that chemical reaction at the mask surface reduce s the vapor phase concentration of group III source materials. This as sumption successfully quantitatively predicted the experimental result s.