Comparison of inductively coupled plasma Cl2 and Cl4/H2 etching of III-nitrides

A parametric study of etch rates, selectivity, surface morphology and etch anisotropy has been performed for Cl2 and CH4/H2 inductively coupled plasma (ICP) patterning of GaN, AlN, InN, InAlN, and InGaN at low dc self-biases (typically ⩽−100 V). Controlled etch rates in the range 500–1500 Å min−1 are obtained for all materials. Surface morphology is a strong function of ion energy and plasma composition in both chemistries, while vertical sidewalls are obtained over a wide range of conditions because of the ion-driven nature of the etch mechanism.