Elasticity-based theory of misfit-induced structural defects at semiconductor interfaces

In this paper, we consider the problem of the determination of misfit-induced structural features at the interface of semiconductor heterostructures. We then develop a theory which enables us to investigate these features. This theory is based on the elasticity equations within the range of application of Hooke's law. The main aim of the theory is the determination of the parameter n(s) which defines the superstructure which may stabilize the interface between the host materials constituting the heterostructure. This is done by identifying, in the elasticity equations, the S factor, i.e., S = C-ij/rho, as the important parameter which must be considered within an approach which takes account not only of the mismatch of the lattice parameters of the host materials, but also of the difference in elastic-density features. The periodic sites of the defined super unit cell, induced by the misfit, may be considered as nucleation centers for misfit-dislocations network. Due to the lattice misfit, one must seek an optimized choice of the materials and of the growth conditions. In heterostructures where a large misfit exists, the insertion of a transitional layer aiming to obtain high-quality heterostructures may often be useful. We demonstrate that the present theory may be used to predict the composition of such transitional layers.