Abstract: A systematic study of etch rates and selectivities of GaN and Al_0.27Ga_0.73N at different processing terms is performed using Cl₂/Ar inductively coupled plasma. Selectivity between GaN and Al_0.27Ga_0.73N decreases with the increasing DC bias and changes a little with ICP power. Adding O2(10%) to Cl₂/Ar(3:1) gas mixture has little effect on etch rates of GaN, but leads to a great reduction in etch rates of Al_0.27Ga_0.73N, thus improving selectivity between GaN and Al_0.27Ga_0.73N. Schottky characteristics at different etching DC biases are contrasted, with the result that the leakage current increases with the enhanced DC bias.

Key words: Inductively coupled plasma, etching rates, selective etch；selectivity, etching damage