Study on ICP Etching Induced Damage in p-GaN

The plasma-induced damage for p-GaN by inductively coupled plasma(ICP) etching with Cl2/N2 gas chemistry was studied.Effects of ICP power,RF power,chamber pressure,and Cl2 percentage on the physical and electrical characteristics of p-GaN were investigated.The results show that the surface roughness is relatively independent of these etching conditions and shows fairly smooth morphology (RMS＜1.2nm);the surface morphology has no direct effect on the electrical characteristics of p-GaN,and the deterioration of ohmic contact to the etched p-GaN is due to a decrease in hole concentration in the near-surface region through the creation of shallow donor states rather than surface roughening.