The behavior of off-state stress-induced electrons trapped at the buffer layer in AlGaN/GaN heterostructure field effect transistors

Abstract

A measurement methodology involving the synchronous switching of gate to source voltage and drain to source voltage (VDS) was proposed for determining the shift of threshold voltage after an AlGaN/GaN heterostructure transistor endures high VDS off-state stress. The measurement results indicated slow electron detrapping behavior. The trap level was determined as (EC – 0.6 eV). Simulation tool was used to analyze the measurement results. The simulation results were consistent with the experimental results; and a relationship between the buffer trap and threshold voltage shift over time was observed.