Chlorine-Based High Density Plasma Etching Of Alpha-Ga2o3 Epitaxy Layer

High density plasma etching of alpha-Ga2O3 epitaxy layer was performed in chlorine-based (Cl-2/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 alpha-Ga2O3 etch rate increased as Cl-2 or BCl3 content in the gas mixture and ICP source power increased, and Cl-2/Ar ICP discharges produced higher etch rates than BCl3/Ar discharges under the conditions examined. Increasing rf chuck power was found to increase the alpha-Ga2O3 etch rate and to improve surface morphology of the etched field. The highest etch rates of similar to 612 angstrom/min and similar to 603 angstrom/min were obtained in 13Cl(2)/2Ar and 13BCl(3)/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 alpha-Ga2O3 layer using a 10Cl(2)/5Ar ICP discharge.[GRAPHICS].