STEP-FLOW GROWTH ON STRAINED SURFACES

A theoretical study is presented of the effect of misfit strain on the transition from step flow to island nucleation dominated epitaxial layer growth on a vicinal surface. The analysis generalizes a set of reaction-diffusion equations used for homoepitaxy to include the fact that heteroepitaxial strain changes the Arrhenius barrier for diffusion and promotes the detachment of atoms from the edge of strained terraces and islands. The first effect is equivalent to changing the deposition flux; the latter can drive the system into a new layer growth mode characterized by moving steps that engulf very many very small islands. Experiments to test these predictions are suggested.