Effects of Mask Imperfections on InP Etching Profiles

We have demonstrated that the quality of etch masks has a significant effect on the etching profiles. In particular, we have shown that mask imperfections can cause defective etching profiles, such as vertical sidewalls and extra mask undercutting in . We also discovered that the geometry of these defective profiles is determined by the orientation of the substrate relative to the direction of the mask imperfections. Along a <110> line mask defect, the downward etching process changes the <110> v‐grooves to vertical sidewalls without extra undercutting. For v‐grooves aligned along the <110> direction, defects on the mask give a significant extra undercutting without changing the etching profile.