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

Abstract: High density plasma etching of α-GaO epitaxy layer was performed in chlorine-based (Cl/Ar and BCl/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-GaO etch rate increased as Cl or BCl content in the gas mixture and ICP source power increased, and Cl/Ar ICP discharges produced higher etch rates than BCl/Ar discharges under the conditions examined. Increasing rf chuck power was found to increase the α-GaO etch rate and to improve surface morphology of the etched field. The highest etch rates of ~ 612 Å/min and ~ 603 Å/min were obtained in 13Cl/2Ar and 13BCl/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-GaO layer using a 10Cl/5Ar ICP discharge. Graphic Abstract: [Figure not available: see fulltext.].