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 Cl-2/Ar etching provides smoother N-face surfaces even at high etch rates. The dependence of the etch rate on the Cl-2 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.