Reactive ion etching of GaN/InGaN using BCl₃ plasma

Reactive ion etching (RIE) of GaN and InGaN using BCl₃ plasma under a high self-bias voltage was carried out. The effects of rf plasma power, chamber pressure and BCl₃ flow rate on the etch rate were investigated. An etch rate as high as 132nmmin^-1 for GaN was obtained under an rf power of 200W, a BCl₃ flow rate of 2sccm and a pressure of 25mTorr. The root-mean-square roughness of the etched surface was between 2.5 and 3nm as determined by atomic force microscopy. It was also found that the etch rate for InGaN under the same conditions was slightly higher than those for GaN. Photoluminescence measurements revealed that the damage due to RIE could be recovered significantly by a short-time thermal annealing process.