Kinetic Models of Epitaxial Growth: Theory and Experiment

We examine the morphological evolution of growing surfaces using Monte Carlo simulations of a solid-on-solid model. We use direct comparisons with experiment both to identify the kinetic processes that must be included in a model for GaAs(001) homoepitaxy and to parametrize the rates of these processes. We first examine the evolution of a vicinal surface during the first few monolayers of growth and compare the density of surface steps of the simulated surfaces with reflection high-energy electron-diffraction measurements. By including both a non-thermal incorporation step of freshly deposited atoms and a barrier to interlayer atomic transport, excellent quantitative agreement is obtained for an entire range of growth conditions, including the relaxation of the surface toward equilibrium upon the termination of the beam. We then examine the morphology as successively more layers are grown and find that the surface evolves into a self-organized state wherein the local slope of the growing features remains approximately constant with time.