COMPOSITIONAL NONUNIFORMITIES AND STRAIN RELAXATION AT MISORIENTED INXGA1-XAS GAAS INTERFACES

Compositional nonuniforimities and misfit dislocations are observed ne ar misoriented In0.2Ga0.8As/GaAs interfaces. The compositional nonunif ormities result from In interdiffusion at the interface over a distanc e of 3 nm and formation of InAs platelet precipitates. The misfit disl ocations are of pure edge and 60-degrees types. The core of pure edge misfit dislocations generally consists of two 60-degrees dislocations separated by approximately 2.5 nm. One of these 60-degrees dislocation s is usually split into partials and decorated by platelets of InAs. T he interface and surface morphologies are strongly influenced by the s ubstrate tilt away from exact [001] crystallographic orientation.