Implementation of slow and smooth etching of GaN by inductively coupled plasma

Slow and smooth etching of gallium nitride (GaN) by BCl₃/Cl₂-based inductively coupled plasma (ICP) is investigated in this paper. The effects of etch parameters, including ICP power, radio frequency (RF) power, the flow rate of Cl₂ and BCl₃, on GaN etch rate and etch surface roughness RMS are discussed. A new model is suggested to explain the impact mechanism of the BCl₃ flow rate on etch surface roughness. An optimized etch result of a slow and smooth etch surface was obtained; the etch rate and RMS were 0.36 Å/s and 0.9 nm, respectively. (paper)