Misfit dislocations and surface morphology of lattice-mismatched GaAs/InGaAs heterostructures

A regular network of 60° misfit dislocations aligned along two orthogonal 〈110〉 directions at the (001) interface of GaAs/InGaAs heterostructures with a small lattice-mismatch has been revealed by means of transmission electron microscopy and electron-beam induced current mode in a scanning electron microscope. The network of misfit dislocations has been also reproduced, in a form of a well-defined cross-hatch pattern on the surface of the structures, with atomic force microscopy. Almost one-to-one correspondence between the structure of misfit dislocations at the interface and the surface morphology clearly demonstrate that the cross-hatch development results primarily from misfit-dislocation generation.