Self-organization on semiconductor surfaces: fundamental thermodynamic issues

Fundamental thermodynamic issues are surveyed to establish limits of the degree of spatial ordering during phase separation processes on semiconductor surfaces. The study is based on a detailed experimental investigation 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 principle to extrapolate observed properties to a wide range of length scales. Two basic concepts are discussed to understand the limitations of ordering: (i) the role of screening of the interaction between clusters during phase separation and (ii) the interplay between spatial ordering and size ordering of the clustered phase. (C) 1998 Elsevier Science B.V. All rights reserved.