Continuum and semi-discrete simulations of heteroepitaxial semiconductor relaxation by dislocations

Abstract

The second major thrust of the thesis was to understand how asymmetric strain conditions lead to changes in the relaxation rate and also the final strain in the layer. Such asymmetric strain arises both from differences in the interfacial in-plane lattice parameters and relaxation mechanisms in different in-plane directions. A reformulation of the isotropic linear elastic equation for applied dislocation stress was derived, leading to the conclusion that when one in-plane direction is not relaxed, the orthogonal direction over-relaxes in response. Simulation results for this mechanism are presented for both SiGe/Si(110) and a-plane AlGaN/GaN.