BCl3-Based Dry Etching of Exfoliated (100) -Ga2O3 Flakes

We report on BCl3-based dry etching characteristics of (100) β-Ga2O3 flakes using inductively coupled plasma etching technique, which were prepared by mechanical exfoliation from Ga2O3 single crystal. The etch rate of (100) Ga2O3 flake increased with increasing bias rf powers up to 52 nm min-1 using 25 sccm BCl3/15 sccm N2 gas chemistry. We also examined the etch rate dependence of Ga2O3 on crystal orientation. The (100) Ga2O3 flake has the lowest etch rate when compared with (010) and Ga2O3 surfaces. The lowest etch rate of (100) Ga2O3 surface results from less Ga-O bond breaking efficiency and low dangling bond density on the surface. It is notable that Ga2O3 surface is etched at higher rate than (010) and (100) Ga2O3 surfaces. The surface morphologies of etched (100) Ga2O3 surface exhibited little change, and rms roughness values remained less than 1.5 nm over a broad range of etch conditions.