Parametric study of inductively coupled plasma etching of GaN epitaxy layer

Abstract

The effect of process parameters such as plasma composition, ICP (Inductively Coupled Plasma) source power and rf chuck power on the etch characteristics of GaN epitaxy layer was studied. Cl 2 /Ar ICP discharges showed higher etch rates than SF 6 /Ar discharges because of the higher volatility of GaCl x etch products than GaF x compounds. As the Ar ratio increases in the Cl 2 /Ar ICP discharges, the etch anisotropy was enhanced due to the improved physical component of the etching. For both plasma chemistries, the GaN etch rate increased continuously as both the ICP source power and rf chuck power increased, and a maximum etch rate of 251.9 nm/min was obtained at 13Cl 2 /2Ar, 750 W ICP power, 400 W rf chuck power and 10 mTorr condition.