ATOMISTIC NUMERICAL STUDY OF MOLECULAR-BEAM-EPITAXIAL GROWTH-KINETICS

We report on the results of a stochastic Monte Carlo simulation study of molecular-beam epitaxial-growth dynamics with particular emphasis on the role of atomistic kinetic processes on crystal-growth quality. Using a model that goes beyond the standard solid-on-solid approximation and allows for vacancies and overhangs, we investigate the effect of bulk vacancies on the growth dynamics. Based on our simulation results, we discuss the role of reflection high-energy electron diffraction (RHEED) intensity oscillations in determining the growth quality and the interplay between the growth rate and the various intrinsic kinetic rates, such as intralayer and interlayer diffusion rates in the growth dynamics. We dynamically calculate the multilayer surface coverage, the surface roughness, the defect density, and the RHEED intensity (at the anti-Bragg condition) for scattering from the growing crystal for our growth model. Our simulated results are in excellent qualitative agreement with the available experimental data. Based on our simulation results, we emphasize the kinetic basis of molecular-beam epitaxial growth.