Controlled Undercutting of V‐Groove Channels for InP by Photoresist Etch Mask

A photoresist etch mask process has been developed for the etching of v‐grooves in (001) for channeled substrate laser growth. The relationship between the photoresist (PR) mask undercutting and the dehydration bake temperatures, the postbake temperatures, and the photoresist thicknesses were studied. The native oxide growth during the bake processes was believed to give the extra large undercut.