An investigation was made of surface kinetics, during metal-organic vapor-phase epitaxial growth, by means of high-vacuum scanning tunnelling microscopic observations of 2-dimensional nuclei and denuded zones. Monte Carlo simulations were carried out which were based upon the solid-on-solid model. Two-dimensional nucleus densities were used to deduce that the surface diffusion coefficient was equal to 1.5 x 10-7cm2/s at 530C. The activation energy for migration was estimated to be 0.80eV. The 2-dimensional nucleus size in the [110] direction was about twice that in the [¯110] direction. This anisotropy was attributed mainly to a difference in the lateral sticking probabilities between steps along [¯110] and those along [110]. The ratio of the sticking probabilities was estimated to be greater than 3:1. The denuded zone widths on the upper terraces were some 2 times wider than those on the lower terraces. This suggested that the sticking probability at descending steps was 10 to 300 times larger than the probability at ascending steps.

M.Kasu, N.Kobayashi: Journal of Crystal Growth, 1997, 170, 246-50