Characterization of Dynamic $I_{\text{OFF}}$ in Schottky-Type $p$-GaN Gate HEMTs

Abstract

In this work, systematic characterization of dynamic OFF-state leakage current ( $\boldsymbol{I}_{\mathbf{OFF}}$ ) in Schottky-type $\boldsymbol{p}$ -GaN gate high-electron-mobility transistors (HEMTs) is presented based on pulsed I-V measurement and consecutive switching measurement. The high $\boldsymbol{I}_{\mathbf{OFF}}$ under dynamic pulse mode without hole injection is found to be a result of the reduced voltage blocking capabilities (both lateral and vertical) with weaker trapping effect in the buffer, and the dynamic $\boldsymbol{I}_{\mathbf{OFF}}$ induced by ON-state hole injection is attributed to further increased lateral conductivity through the buffer from source to drain. Under continuous ON/OFF switching operation, saturation of dynamic $\boldsymbol{I}_{\mathbf{OFF}}$ is observed due to a balanced trapping/de-trapping process of buffer traps. Higher temperature is found to be beneficial to the reduction of the dynamic $\boldsymbol{I}_{\mathbf{OFF}}$ induced by ON-state hole injection, and a sufficiently large negative OFF-state gate bias ( $\boldsymbol{V}_{\mathbf{GS},\mathbf{OFF}}$ ) of −3 V is shown to completely eliminate the dynamic $\boldsymbol{I}_{\mathbf{OFF}}$ induced by hole injection to minimize the OFF-state power consumption in practical power switching applications.