Morphological Evolution of Strained Films by Cooperative Nucleation

Abstract

We identify a new mechanism of stress driven surface morphological evolution in strained semiconductor films. Surface roughness forms by a cooperative mechanism involving the sequential nucleation of islands and pits, which is distinct from the conventional view of ripple formation as an Asaro-Tiller-Grinfeld (ATG) instability. This mechanism is operative both during annealing and growth and competes with the ATG instability as a kinetic pathway to ripple formation.