TCAD Modeling of the Dynamic VTH Hysteresis Under Fast Sweeping Characterization in p-GaN Gate HEMTs

Abstract

TCAD modeling of the dynamic threshold voltage shift (hysteresis) occurring under fast sweeping characterization in Schottky-type p-GaN gate high-electron-mobility transistors (HEMTs) is reported, to the best of our knowledge, for the first time. Dynamic $V_{TH}$ hysteresis has been first experimentally characterized under different sweeping times, temperatures, and AlGaN barrier configurations. Then, TCAD simulations have been carried out, reproducing the experimental evidences and understanding the microscopic mechanisms responsible for such effect. In particular, nonlocal tunneling models implemented in Sentaurus TCAD, defined at the gate Schottky contact and assisted by traps in the AlGaN barrier layer, have been adopted and properly tuned against experiments. Results show that the dynamic $V_{TH}$ hysteresis is mainly caused by the time-dependent hole charging/discharging processes in the floating p-GaN layer, which are governed by the Schottky and AlGaN barrier leakage current components.