Chlorine-based inductive coupled plasma etching of <i>α</i> -Ga ₂ O ₃

Abstract

Abstract Dry etching behavior of unintentionally-doped α -Ga 2 O 3 was investigated in a BCl 3 /Cl 2 /Ar chemistry using inductively-coupled-plasma technique. We systematically studied the impact of various etch conditions such as BCl 3 /Cl 2 /Ar gas ratio, plasma and bias powers, and chamber pressure on etch rate, surface roughness and mask selectivity of α -Ga 2 O 3 with respect to Si 3 N 4 , SiO 2 and photoresist. In contrast to GaN etching, Cl 2 was found to be far less effective than BCl 3 in etching α -Ga 2 O 3 .