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 la yer growth on a vicinal surface. The analysis generalizes a set of rea ction-diffusion equations used for homoepitaxy to include the fact tha t heteroepitaxial strain changes the Arrhenius barrier for diffusion a nd promotes the detachment of atoms from the edge of strained terraces and islands. The first effect is equivalent to changing the depositio n flux; the latter can drive the system into a new layer growth mode c haracterized by moving steps that engulf very many very small islands. Experiments to test these predictions are suggested.