Mapping of photo-electrochemical etched Ni/GaN Schottky contacts using scanning internal photoemission microscopy—comparison between n- and p-type GaN samples

Abstract

We present the experimental results on mapping characterization of the effects of photo-electrochemical (PEC) and inductive coupled plasma (ICP) etchings for both p-type and n-type GaN Schottky contacts by using scanning internal photoemission microscopy to clarify the current transport mechanism. The photoyield (Y) increased in the PEC etched regions by 4%–5% for the n-GaN, by 15% for the p-GaN samples. We proposed a model that the ICP etching induced donor-type damages in the vicinity of the GaN surfaces. In the ICP etched regions, Y increased by 10% for the n-GaN as well, but significantly decreased by 80% for the p-GaN samples. The PEC etching has less effect on the Schottky characteristics than the ICP etching, especially in the p-type sample.