Effects of BCl3 addition to Cl2 gas on etching characteristics of GaN at high temperature

Gallium nitride films were etched at 400 degrees C and 20 Pa with a radio-frequency-generated Cl-2-BCl3 mixed plasma. While dog-legged profiles were obtained by plasma etching using pure Cl-2, straight sidewall shapes were achieved through BCl3 gas addition into the Cl-2 plasma by suppressing the plasma-induced damage on the etched surface. Etching by-products containing boron on the etched surface affected the etch rate. Smooth etched profiles were obtained by controlling the redeposition of by-products of boron and chlorine compounds, particularly for substrate temperatures above 230 degrees C. Published by the AVS.