Misfit-Dislocation Induced Surface Morphology of InGaAs/GaAs Heterostructures

The correlation between the surface cross-hatched morphology and the interfacial misfit dislocations in partially relaxed InGaAs/GaAs heterostructures was studied by means of atomic force microscopy and electron-beam induced current mode in a scanning electron microscope. A close correspondence between the misfit-dislocation network at the interface and the surface morphology shows that the cross-hatch development results primarily from the misfit-dislocation generation. Statistical analysis of the surface roughness reveals an anisotropy in strain relaxation of the epitaxial layers, which results from an asymmetry in the misfit-dislocation formation.