Defect reduction in GaAs grown by molecular beam epitaxy using different superlattice structures

Several superlattice structures, grown by molecular beam epitaxy, have been used to reduce the density of threading dislocations originating from the GaAs substrate. Results clearly indicate that compared to epitaxial layers grown directly on GaAs substrates, a GaAs-InxGa1−xAs superlattice (x<0.12) reduces the dislocations by approximately two orders of magnitude. Transmission electron microscopy, electron beam induced current, and etch pit density have been used to characterize the effectiveness of using superlattice buffer layers for the reduction of defects in GaAs epilayers.