The relaxation of epitaxial islands

A numerical model based on the variational principle is developed to model the kinetics and thermodynamics of microstructural evolution in multi-compo nent systems under the influence of elastic stored energy variations. The d riving force due to the elastic stored energy is implemented in a consisten t manner such that it acts to reduce the global elastic strain energy. The model is used to look at the evolution of epitaxially strained InAs islands grown on a GaAs substrate in two simplified cases: for the situation where surface diffusion dominates and the island relaxes by changing its shape, and for the situation where lattice diffusion dominates and the island rela xes by changing its compositional profile.