DISLOCATION BEHAVIOR AT HETEROINTERFACES IN III-V SEMICONDUCTORS

Interfaces between epitaxial layers with different lattice parameters often contain relatively simple arrays of misfit dislocations. The configuration in which a thin layer in compression relaxes by the introduction of two sets of orthogonal misfit dislocations has been widely studied. In this paper three less straightforward situations are considered. Interfaces on vicinal planes are shown to contain four arrays of dislocations which cross at small angles. Layers under tensile strain can relax by several mechanisms, and it is pointed out that strained layers never relax fully to give a strain-free surface. The implications of these observations are considered.