Cooperative ridge-trench formation in heteroepitaxial systems

Abstract

In this paper we investigate the cooperative ridge-trench formation from the theoretical point of view. Our investigation starts with numerical simulation for the morphological evolution of strained film-substrate system driven by surface diffusion. The results demonstrate that the morphological evolution of thick films leads to the unique cooperative formation of faceted trenches and ridges. The cooperative formation is further analyzed from the energy point of view by considering the two pathways of the cooperative formation, namely, the growth of the outermost structure and the gradual formation of a faceted structure adjacent to the existing one. The analyses reveal that the first pathway dictates the process initially, while the second one is more energetically favorable once the size of the outermost structure reaches a critical value. The competition of the two pathways repeats, resulting in the cooperative ridge-trench formation. © 2007 The American Physical Society.