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

We investigated the growth mechanism of selective area metalorganic vapor phase epitaxy (MOVPE) on planar mask-patterned substrates by analyzing the growth pressure dependence of the in-plane growth rate distribution using an equation we reported previously [T. Fujii, M. Ekawa and S. Yamazaki, J. Crystal Growth 146 (1995) 475]. Experiments showed that the lateral diffusion constants defined at the epilayer and mask surfaces 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 predicts, however, that enhancement is proportional to growth pressure when the growing probability on the mask surface is exactly zero, This contradiction suggests that chemical reaction at the mask surface reduces the vapor phase concentration of group III source materials. This assumption successfully quantitatively predicted the experimental results.