Strain relaxation in the growth of planar InAs

Abstract

In this work, we look at the strain relaxation of InAs growth on GaAs under metal rich conditions. InAs layers, grown under these conditions, have been found to maintain a planar morphology for thicknesses well beyond a Matthews-Blakeslee critical thickness of ∼2 ML. We employed reflection high-energy electron diffraction, in situ spectroscopic ellipsometry and atomic force microscopy to follow the InAs growth under In stabilized conditions. The critical thickness was found to increase with a reduction in growth temperature. A region of growth was seen in which three-dimensional diffraction was not visible in the reflection high energy electron diffraction pattern before annealing. For thicknesses less than the critical thickness observed by atomic force microscope, the planar morphology has been found to be stable with annealing. These results indicate that strain relaxation via the formation of Lomer-type dislocations is essential to stabilizing planar morphology during growth.