The effect of plasma anodization on AlGaN/GaN HEMT

Abstract

AlGaN/GaN high electron mobility transistors (HEMTs) were fabricated and the source and drain regions of the HEMTs were plasma-treated and anodized to investigate the effect of plasma anodization. The anodization was executed in N2O plasma by applying a bias of 20 V to the source and drain region under illumination of deep UV for the activation of the AlGaN surface. The gate leakage current of the HEMT decreased by two orders of magnitude after anodization. However, it was not varied by plasma treatment which was the same as for the anodization process except for the bias. Despite the reduction of gate leakage current, the threshold voltage was not varied and the transconductance and drain saturation current were increased slightly by the anodization.