Dynamic Interplays of Gate Junctions in Schottky-type p-GaN Gate Power HEMTs during Switching Operation

Dynamic behaviors of threshold voltage (VTH) of the Schottky-type p-GaN gate high-electron-mobility transistor (HEMT) have been intensively studied in recent years, which is vital to properly operate the device and leverage its full potential. Most research has focused on impacts of individual terminal biases, i.e., either drain-to-source (VDS) or gate-to-source (VGS) voltages. However, devices are subject to continuous switching with alternating VGS and VDS in actual application scenarios. This work reveals that the charge storage mechanism of VDS-induced dynamic VTH, which is associated with the two back-to-back junctions in the gate stack, also governs the VGS-induced VTH variation. Therefore, both VDS-and VGS-induced dynamic VTH behaviors could be accurately described with a unified equivalent circuit-based SPICE model, which in turn visualizes the dynamic interplays of the two gate junctions and demonstrates the capability of predicting devices’ dynamic behaviors in real switching operations.