Direct Observation of Dislocations in Ga1 − x Al x As ‐ GaAs Grown by the LPE Method

Abstract

Transmission x‐ray topographs of thick LPE layers grown on (001) substrates were obtained by a double crystal Lang technique using monochromatic divergent radiation and compared with the etch pit pattern revealed by molten . It was observed that most threading dislocations bend abruptly at the interface. Although the substrate parts of these dislocations were of various types, the epitaxial parts were clearly classified as either [001] oriented, β‐, or arc‐like dislocations. Nonequivalent behavior of threading dislocations between the two directions was observed. Some effects due to melt‐back of the substrate prior to the epitaxial growth are discussed.