Published online by Cambridge University Press: 15 February 2011
Within a valence force field framework, we calculate the critical thickness of a film lattice mismatched to the substrate on which it is epitaxially deposited. A capping layer lattice matched to the substrate is known to enhance the critical thickness. We calculate the efficiency of the capping layer and study how the capping layer thickness modifies this efficiency. We also demonstrate how using a capping layer which is no more lattice matched to the substrate may improve the effect of the capping layer. Extension to strain compensation in multilayer systems is provided. In the case of uncapped systems, or systems with a thick capping layer lattice matched to the substrate, the results we have obtained using a microscopic description are compared to recent results, obtained using continuous classical elasticity.