Inductively coupled plasma etching of GaN using Cl 2/He gases

Abstract

We investigated n-GaN etched by an inductively coupled plasma (ICP) etcher using Cl 2/Ar and Cl 2/He as the etching gases. A detailed study on the samples etched in different ICP power, RF power, process pressure and Cl 2/Ar(He) mixing ratio was performed. It was found that n-GaN could be successfully etched by both Cl 2/Ar and Cl 2/He. The maximum etching rate could reach 8000 Å min −1 for n-GaN etched in Cl 2/Ar and 8400 Å min −1 for n-GaN etched in Cl 2/He. Furthermore, it was found that the specific contact resistance is 4.2×10 −4 and 1.37×10 −6 Ω-cm 2 for n-GaN etched by Cl 2/Ar and Cl 2/He, respectively. The smaller contact resistance is probably due to the lighter He which induce smaller plasma damages during ICP etching.