Comparison of inductively coupled plasma chemistries for dry etching of group III-nitrides

A comparison of etch characteristics of GaN, InN and AlN has been performed in boron halides- (BCl3, BI3, and BBr3) and interhalogen- (ICI and IBr) based Inductively Coupled Plasma (ICP) discharges. An etch rate of 1.1 mum/minute, the highest value reported for InN and etch selectivities of similar to25 for InN over AlN and similar to7 for InN over GaN were obtained in BCl3 ICP discharges. Etch selectivities similar to100 for InN over GaN and AlN are obtained in BI3 due to the relatively high volatility of the InIx etch products and the lower bond strength of InN. Maximum selectivities of similar to10 for InN over GaN and similar to30 for InN over AlN were obtained with ICI and IBr chemistries. The etched surface morphologies of GaN in BI3, BBr3, ICI and EBr mixtures are similar or better than those of the control sample.