On the Formation of Planar‐Etched Facets in GaInAsP / InP Double Heterostructures

Techniques to predict and control the etched wall profile at a mask edge are developed. An understanding of the etch rate vs. substrate orientation angle is used to predict and experimentally realize desired etched wall profiles on (001) double heterostructure (DH) wafers. The identification and utilization of crystallographic stop etch planes is key to ensuring planar and reproducible etched facets. Fabrication procedures employing wet and dry etching techniques are outlined for either isolated step‐etched vertical wall profiles or narrow groves.