Evaluation and Numerical Simulations of GaN HEMTs Electrical Degradation

In this letter, the effects of dc stress on GaN high-electron-mobility transistors´ performance are investigated by means of experimental measurements and numerical simulation. A degradation of both dynamic (pulsed I-V) and static characteristics (dc) has been observed on stressed devices, and it has been experimentally related to the formation of an electron trap in the AlGaN barrier layer. Numerical simulations carried out on the tested structure by introducing a trapping region at the gate edge of the device barrier confirm the experimentally observed device degradation. The worsening of the dynamic performance is induced by both an increase in trap concentration and/or depth of the trapping region while the degradation of the dc characteristics can be explained by an increase in the trapping-region depth.