Chlorine-based inductive coupled plasma etching of α-Ga₂O₃

Dry etching behavior of unintentionally-doped α-Ga₂O₃ was investigated in a BCl₃/Cl₂/Ar chemistry using inductively-coupled-plasma technique. We systematically studied the impact of various etch conditions such as BCl₃/Cl₂/Ar gas ratio, plasma and bias powers, and chamber pressure on etch rate, surface roughness and mask selectivity of α-Ga₂O₃ with respect to Si₃N₄, SiO₂ and photoresist. In contrast to GaN etching, Cl₂ was found to be far less effective than BCl₃ in etching α-Ga₂O₃. (paper)