A deep trench is etched in a silicon wafer using DRIE. The trench measures 20 µm × 100 µm. After removing all protecting layers on the trench wall, the trench is further etched in KOH. Describe the...

A deep trench is etched in a silicon wafer using DRIE. The trench measures 20 µm × 100 µm. After removing all protecting layers on the trench wall, the trench is further etched in KOH. Describe the final shape of the trench after KOH etching if the wafer orientation is (a) {100}, (b) {110}, or (c) {111}.