Enhanced wet etching of patterned GaN with heavy-ion implantation

We present the enhanced wet etching of GaN epilayer implanted with Au⁺ ion. Patterned GaN with 2 ¿m-wide sink-like strips was achieved by using 500 keV Au⁺ ion implantation and KOH etching. The dependence of etching depth on etching time for the implantation at different ion fluences was investigated. Erosion of GaN surface was obvious with implantation at the fluence of 3×1016 cm^-2. The experiment showed that the damaged GaN area could be completely etched out at high ion fluence, and the etching depth could exceed the project range of incident 500 keV Au⁺ ion. The ~400 nm depth etching could be achieved with high fluence implantation and a long etching time, and the edge of etched area could remain clear until the etching process passes 80 mins. As-deposited SiO₂ spheres were used to mask the GaN sample in implantation process to investigate the etching effect. ~70 nm wave of the GaN surface was observed. The results of our experiments may suggest an approach to the fabricating of GaN devices.