Inductively coupled plasma etching of GaN using Cl2/Ar and Cl2/N2 gases

This work investigates inductively coupled plasma (ICP) etching processes of GaN. Etching behaviors are also characterized by varying the ICP power, Cl2/Ar or Cl2/N2 mixing ratio, radio-frequency (rf) power, and chamber pressure. Experimental results indicate that the etching profiles are highly anisotropic over the range of etching conditions. Maximum etching rates of 8200 Å/min in Cl2/Ar plasma and 8330 Å/min in Cl2/N2 plasma are obtained as well. In addition, pressure, ICP power, Cl2/Ar(N2) flow ratio and rf power significantly influence etching rate and surface morphology. In particular, dc bias heavily influences the etching rates, suggesting that the ion-bombardment effect is an important factor of these etching processes.