A highly effective technique for etching large batches of GaN wafers, by means of Inductively Coupled Plasma (ICP) tools, has been developed. A variety of 27 × 2 inch wafer batch processes have been investigated and etch rates in excess of 140nm/min with selectivity of 0.9:1 to photoresist (PR) has been achieved.

Particularly, a special active spacer was designed and employed in the ICP system to control plasma profile during the processes. This technique was favourable for increasing etch rates and achieving good uniformities. Using this system a wafer-to-wafer batch uniformity of ±4% was realized.