Perturbation-induced compositional instability in epitaxial binary-alloy films

We examine the thermodynamic kernel that underpins dynamic models of instability in planar semiconductor alloys and explain how the energetics of perturbation produce decomposition in normally miscible alloys. By considering the relationship between epitaxial surface strain and the perturbation geometry, we show that amplification of the surface strain is the elastic cause of instability. We conclude by developing a nonlinear stability diagram for large-amplitude perturbations; configurational entropy terminates the growth of linearly unstable perturbations.