Orientation dependentp-type conversion of Fe:InP in hydride VPE regrown EMBH lasers

We have studied semi-insulating Fe:InP regrowth of etched mesa buried heterostruc-ture lasers by hydride vapor phase epitaxy. Type-sensitive staining and electron beam induced current photographs have shown that regions near the original etched mesa are p-type instead of semi-insulating in a number of our wafers. These regions begin and end on distinct crystal boundaries, indicating that thep-type conversion is not due to simple diffusion of Zn out of the laser base structure, but is associated with uncontrolled growth of {111}_In crystal planes.