Degradation and Recovery Property of Schottky Barrier Height of AlGaN/GaN High Electron Mobility Transistors under Reverse AC Electrical Stress

We apply a reverse AC electrical stress on the Gate of AlGaN/GaN high electron mobility transistors (HEMTs). The change of Schottky Barrier height (SBH) with respect to time is derived from the I-V and C-V characteristics, respectively. The SBHs calculated from the two methods show similar decreasing trend. However, the one from I-V method recovers partly after stress is removed. The behaviour is attributed to the traps in AlGaN barrier and surface state of the gate as a result of the electrical stress, and the recovery of surface state is the main factor for the recovery phenomena.