Reactive ion etching of gallium nitride usinghydrogen bromide plasmas

The characteristics of the reactive ion etching (RIE) of gallium nitride (GaN) have been investigated using HBr, 1:1 HBr:Ar, and 1:1 HBr:H2 plasmas. Etch rates were found to increase with plasma self-bias voltage for all gas mixtures exceeding 60 nm/min at –400 V for pure HBr. Higher etch rates were obtained for pure HBr than for HBr mixtures with Ar and H2. Chamber pressure was also found to slightly affect etch rates for the pressure ranges investigated. The anisotropy of etched profiles was found to improve with increasing pressure. Smooth etched surfaces are also demonstrated.