Stacking Faults and Substructure in GaAs / ( Ga , Al ) As Heteroepitaxial Layers: I . Origin and Elimination

Abstract

The origin of stacking faults and substructure observed in layers grown by liquid phase epitaxy on Syton polished substrates has been studied. The stacking faults primarily originate at the substrate‐epilayer interface. These faults presumably occur to accommodate misfit between coalescing islands observed in the early growth studies of heteroepitaxy of on these substrates. The island‐like growth appears to correlate with calcium contamination associated with the Syton polished substrates. In addition, dislocation substructure has been observed in and epi‐layers grown on Syton polished substrates. In the case of iso‐epitaxial layers, no stacking faults are seen. Thus growth of a buffer layer of eliminates the stacking faults but not the substructure. It is therefore suggested that the dislocation substructure arises from the replication of dislocations present in deformed surface regions of Syton polished substrates. On the other hand, heteroepitaxial layers of grown on Br‐methanol polished substrates are largely free from these structural defects.