Mechanism of eliminating basal plane dislocations in SiC thin films by epitaxy on an etched substrate

Abstract

Homoepitaxial growth is performed on 8° off-axis SiC substrates that are molten KOH etched. The shape of a basal plane dislocation (BPD) etch pit at different stages of epitaxial growth is studied by atomic force microscopy. It is found that the growth steps covering a BPD etch pit are curved, and both the usual step-flow growth and lateral growth perpendicular to the step-flow direction will take place in the pit simultaneously during epitaxy. The lateral growth is usually dominant and “blocks” the path for the BPD to propagate, and thus the conversion of BPDs to threading edge dislocations is enhanced.