Kinetics of submonolayer and multilayer epitaxial growth

Abstract

An introductory review of the central ideas in the kinetics of submonolayer and multilayer epitaxial growth is followed by a more detailed discussion of some recent developments in the field. The concepts of a critical island size, dynamical scaling of the island-size distribution, and the barrier to interlayer diffusion (Ehrlich-Schwoebel barrier) are introduced. The results of kinetic Monte Carlo simulations of a realistic model of submonolayer epitaxial growth are presented and compared with rate-equation analyses and recent experiments. We also present an analytical expression for the scaled island-size distribution as a function of the critical island size which agrees well with our simulations as well as with experiments. Our results provide a quantitative explanation for the variation of the submonolayer island density, critical island size, island-size distribution and morphology as a function of temperature and deposition rate found in recent experiments. We also present the results of a realistic model for multilayer growth which includes a finite barrier to interlayer diffusion. A method for determining the Ehrlich-Schwoebel barrier based on a comparison of simulations with experimental results for the reflection high-energy electron diffraction intensity, surface width, layer densities, and surface morphology is discussed. In particular, we find that for Fe Fe(100) the interlayer diffusion barrier is significantly less than the activation energy for diffusion on a flat terrace.