Reliability and Stability of Normally-off GaN Power MIS-FETs with LPCVD-SiN<inf>x</inf> Gate Dielectric

Abstract

Time-dependent dielectric breakdown (TDDB), bias-temperature instability (BTI) and reverse-bias step-stress characterizations were conducted to investigate the gate dielectric reliability and threshold voltage stability of the normally-off GaN metal–insulator–semiconductor (MIS-) field-effect transistor (FET) with fully recessed gate structure and highly reliable low-pressure chemical vapor deposition SiN x gate dielectric. The TDDB reveals a long lifetime of the LPCVD-SiN x gate dielectric and highly stable V TH of the MIS-FETs was demonstrated with small BTI. More specifically, hole-induced degradation was revealed by the reverse-bias step-stress tests with various negative gate bias.