Low current dispersion and low bias‐stress degradation of unpassivated GaN/AlGaN/GaN/SiC HEMTs

Abstract

The performance of unpassivated GaN/AlGaN/GaN/SiC HEMTs with intentionally undoped and doped barrier structures are extensively studied. No drain current dispersion between DC and 50 ns pulses on doped devices and less than 10% dispersion on undoped ones is observed. The full (100%) current recovery on undoped sample was measured in 1 µs. The drain current extrapolated from 2 GHz large signal measurements corresponds to the measured static drain current confirming negligible current dispersion of our devices. Insignificant (<5%) degradation in overall device performance parameters (IDs, gm, fT, fmax, Pout) on both undoped and doped structures after 12-hour-long bias stress was obtained. These results documents that suitable device performances can be obtained also on unpassivated GaN-based HEMTs. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)