Samsung Advanced Institute of Technology

Threshold voltage (V_Th) drift of Schottky-type p-GaN gate high-electron mobility transistor (HEMT) was analyzed under high-voltage and hard switching conditions with a resistive load (R-Load). To overcome the distortion in the drain current (I_D) ？ gate voltage (V_G) curve caused by the internal drain capacitance (I_Disp) charging current during the switching transients, a method is presented to accurately measure dynamic V_Th through appropriate correction of I_Disp. The dynamic variation of V_Th was tracked with a gate-drive rise/fall times of 200 ns. During the switching operation, V_Th increases rapidly at the beginning and then saturates at a stable value. This is attributed to the gate forward current during turn-on that increases the hole depletion of the p-GaN gate through the AlGaN barrier. The dynamic V_Th increases linearly at a rate of 40％ with the increase of gate turn-on voltage. V_Th is independent of duty cycle but minorly increases with frequency at high voltages, suggesting that channel hot electrons be injected into the AlGaN barrier and p-GaN.