A closer study on the self-annihilation of antiphase boundaries in GaAs epilayers

The self-annihilation of antiphase boundaries (APBs) in GaAs epilayers is studied experimentally by following the course of the evolution of the APBs in two ways: (1) growing epitaxially GaAs on a GaAs surface which already contained APBs, to investigate the development of the APBs in the new layer by optical microscopy; and (2) layer-by-layer APE-revealing etching followed by mechano-chemical polishing of a GaAs epilayer possessing APBs to study the growth history of APBs. It is found that the self-annihilation of APBs occurs by rearrangement of randomly oriented APBs into ordered APBs, which lie in {011} planes, followed by propagation of APBs along the {011} planes which have an angle of 45 degrees with the (001) surface, until they completely annihilate at their intersections.