Temperature dependent dynamic on-state resistance in GaN-on-Si based normally-off HFETs

摘要

Enhancement-mode GaN-on-Si Hitts for power switching application are investigated under fast switching and elevated ambient temperatures conditions. The switching characteristics are used to evaluate the dynamic on state resistance at temperatures up to 175 degrees C, while switching drain voltage up to 400 V. The devices show a low increase of <25% in dynamic resistance when increasing the ambient temperature up to 125 degrees C. However, differing from expectations, above this temperature a rapid increase of on-resistance up to 85% occurs. Such anomaly indicates the existence of thermally activated trapping processes. Trapping transients taken over a large temperature range and a wide range of off-state stressing time show that in parallel to the buffer trapping, with activation-energy of 0.80 +/- 0.02 eV, an additional de-trapping process with activation energy of 0.42 +/- 0.05 eV occurs through increased leakage current over the temperature. (C) 2016 Elsevier Ltd. All rights reserved.