Photoenhanced wet etching of n-gallium nitride

Photoassisted electrochemical (PEC) etching of n-doped GaN layer grown on saphire in a KOH based solution under illumination of a Hg arc lamp is demonstrated Smooth surfaces were obtained for a narrow range of etching conditions. It was found that this window could be extended by using etch conditions which produced "whiskers". Subsequent post treatment in developer AZ 400K and KOH solution was used to remove these whiskers. An influence of the surface treatment of GaN by wet chemical etching prior to the Schottky barrier metal deposition was investigated.