Reduction of plasma-induced damage in n-type GaN by multistep-bias etching in inductively coupled plasma reactive ion etching

摘要

Plasma-induced damage was reduced by multistep-bias etching that involved a stepwise decrease of the etching bias power (P-bias) and subsequent annealing. The depth of damage at P-bias = 60 W was determined to be 60 nm from the capacitance-voltage characteristics of Ni/Al2O3/etched-GaN metal-oxide-semiconductor diodes. The damaged layer was removed by subsequent etching at P-bias = 5 W and 2.5 W. The residual and shallow damage induced by the low P-bias was then recovered by subsequent annealing at 400 degrees C. The multistep-bias etching of inductively coupled plasma reactive ion etching was thus confirmed to be effective for achieving a high etching rate with low damage. (c) 2019 The Japan Society of Applied Physics