Etching of Ga-face and N-face GaN by Inductively Coupled Plasma

Inductively coupled plasma (ICP) dry etching of metalorganic chemical vapor deposition-grown Ga-face and N-face GaN was performed under various etching conditions. Unlike wet etching, etch rates of the N-face GaN were close to those of the Ga-face GaN for most etching conditions. We also found that BCl3 and SF6 are not suitable for N-face etching, while conventional Cl2/Ar etching provides smoother N-face surfaces even at high etch rates. The dependence of the etch rate on the Cl2 fraction and the plasma condition suggested that adsorption of chlorine onto the GaN surface is the rate-limiting step of the etching at low chlorine coverage conditions, and ion bombardment is the rate-limiting step of the etching at high chlorine coverage conditions.