Theoretical study of GaN growth: A Monte Carlo approach

An atomistic model consistent with a variety of experimental observations is developed for GaN growth by molecular-beam epitaxy. The model is used in Monte Carlo simulation to study the impact of substrate temperature, Ga flux, and V/III (group-V element to group-III element) ratio on growth rate and growth front quality. The growth rate increases with the V/III ratio reaching a saturation value which is determined by the Ga flux. The quality of the growth front improves by using a smaller Ga flux for a fixed temperature and V/III ratio or by reducing the V/III ratio at a given temperature. A consideration of the growth kinetics suggests that GaN grown surfaces are likely to be Ga stabilized. These theoretically estimated trends are evidenced by two-dimensional and three-dimensional growth front contours evaluated under various growth conditions.