Generation-recombination traps in AlGaN/GaN HEMT analyzed by time-domain and frequency-domain measurements: Impact of HTRB stress on short term and long term memory effects

Wide bandgap GaN technology has emerged as a major actor among technologies devoted to high frequency, high power applications. However, GaN based transistors are still largely sensitive to damaging effects induced by interface or surface charges, generally assigned to charge processes induced by spontaneous and piezoelectric effects. This paper presents recent works in the field of reliability on AlGaN/GaN HEMT (High Electron Mobility Transistor), and is focused on the identification and location of activated defects using both pulsed electrical signatures (time domain meas.) and low frequency noise spectra (frequency domain meas.). These sets of measurements partially correlate and give evidence of short term as well as long term memory effects. High thermal reverse bias (HTRB) stress has been applied to a set of devices, and the evolutions of the transistors´ electrical and low frequency noise signatures are investigated.