Fe-Related Trapping and Detrapping Dynamics in AlGaN/GaN HEMTs Inspected by Drain Current Transient (DCT) Spectroscopy

During the large-signal operation of radio frequency (RF) high-electron mobility transistor (HEMT), the output load cycle can cover a large part of the I-V characteristics (device safe operating area) and thus excite trap levels that can limit the RF performance. So, this work aims to inspect the electron trapping and detrapping dynamics in the Fe-doped buffer of 150 nm AlGaN/GaN HEMT at various bias points and pulse widths. The variations in the drain current transient (DCT) amplitude (DIDS) and emission time constant (tn) of the Fe-doping related traps are analyzed using three distinct filling pulses, with varying pulse width from 10 ls to 100 s. The Fe-related trap F1 is determined at EC -0.58 eV by the temperature-dependent DCT measurements. DIDS value depends on ionized acceptor density (trapped electron density) in the HEMT. DIDS is found to increase with the pulse width when the HEMT is exposed to the gate-lag and double-pulsed OFF-state quiescent bias conditions. DIDS of double-pulsed DCT is relatively larger than in other cases. While DIDS of drain-lag DCT remains unchanged over a wide range of pulse durations. Hence, the quiescent bias point is a deciding factor in assessing the trapping effects in the Fe-doped AlGaN/GaN HEMTs.