KINETICS OF SUBMONOLAYER AND MULTILAYER EPITAXIAL-GROWTH

An introductory review of the central ideas in the kinetics of submono layer and multilayer expitaxial 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 distributi on, 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 com pared with rate-equation analyses and recent experiments. We also pres ent an analytical expression for the scaled island-size distribution a s a function of the critical island size which agrees well with our si mulations as well as with experiments. Our results provide a quantitat ive explanation for the variation of the submonolayer island density, critical island size, island-size distribution and morphology as a fun ction 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 si mulations with experimental results for the reflection high-energy ele ctron diffraction intensity, surface width, layer densities, and surfa ce morphology is discussed. In particular, we find that for Fe/Fe(100) the interlayer diffusion barrier is significantly less than the activ ation energy for diffusion on a flat terrace.