Chlorine‐Based High Density Plasma Etching of α-Ga2O3 Epitaxy Layer

Abstract

High density plasma etching of α-Ga2O3 epitaxy layer was performed in chlorine-based (Cl2/Ar and BCl3/Ar) inductively coupled plasmas (ICPs) and the effect of plasma composition, ICP source power and rf chuck power on the etch rate and surface morphology has been studied. The α-Ga2O3 etch rate increased as Cl2 or BCl3 content in the gas mixture and ICP source power increased, and Cl2/Ar ICP discharges produced higher etch rates than BCl3/Ar discharges under the conditions examined. Increasing rf chuck power was found to increase the α-Ga2O3 etch rate and to improve surface morphology of the etched field. The highest etch rates of ~ 612 A/min and ~ 603 A/min were obtained in 13Cl2/2Ar and 13BCl3/2Ar ICP discharges under a moderate source power (500 W) and rf chuck power (250 W) condition, respectively. Anisotropic pattern transfer with a vertical sidewall was performed into the α-Ga2O3 layer using a 10Cl2/5Ar ICP discharge.