SELF-ORGANIZATION ON SEMICONDUCTOR SURFACES - FUNDAMENTAL THERMODYNAMIC ISSUES

Fundamental thermodynamic issues are surveyed to establish limits of t he degree of spatial ordering during phase separation processes on sem iconductor surfaces. The study is based on a detailed experimental inv estigation of diffusion-controlled coarsening (Ostwald ripening) of Sn on Si(111). This late stage process is of particular interest due to the self-similar evolution of the cluster morphology, allowing in prin ciple to extrapolate observed properties to a wide range of length sca les. Two basic concepts are discussed to understand the limitations of ordering: (i) the role of screening of the interaction between cluste rs during phase separation and (ii) the interplay between spatial orde ring and size ordering of the clustered phase. (C) 1998 Elsevier Scien ce B.V. All rights reserved.