Investigation of kink effect in normally-off AlGaN/GaN recessed-gate MOS-heterostructure FETs

Abstract

Kink effects, anomalous increase of the output current, were observed at room temperature in normally-off AlGaN/GaN metal-oxide-semiconductor (MOS)-heterostructure field effect transistors with recessed gate. The kink phenomenon occurred only at certain bias-sweeping conditions and is suggested to result from electron trapping and subsequent detrapping process which gave rise to temporary shift of the threshold voltage. The magnitude of the kink is related to the positive gate bias and the temperature. Positive bias applied on the gate induced the negative charge build-up at the MOS interface and hot electrons released trapped electrons by impact ionization. (C) 2016 American Vacuum Society.