Reactive ion etching of GaN in SF6 + Ar and SF6 + N2 plasma

Abstract

Reactive ion etching (RIE) of GaN using SF6 + Ar and SF 6 + N2 plasma has been carried out. An improvement in etch rate is observed with SF6 + Ar over SF6 + N2 plasma. Schottky diodes fabricated on the etched surface show the evidence of damage. However, damage is less for the samples etched with SF6 + Ar plasma. The reverse leakage current density and the ideality factor are found to depend on the perimeter to area ratio of the device. This suggests that the damage caused by etching is surface damage and the leakage might be because of the formation of a surface channel. Thermal annealing and surface passivation using ammonium sulfide help in recovering the damage. Optimization of annealing as well as passivation schedule is essential, since increased annealing or passivation time degrades the device characteristics. © 2008 IOP Publishing Ltd.