Switching Reliability of NiO/Ga2O3 Bipolar Junction Evaluated by a Circuit Method
Abstract
Ultra-wide bandgap (UWBG) NiO/Ga2O3 bipolar junction has emerged as a critical building block for diverse Ga2O3 power devices, owing to the high breakdown field and avalanche capability. However, the reliability of this bipolar UWBG junction under dynamic switching conditions remains unexplored. In this work, we for the first time characterize the circuit-level switching reliability of large-area NiO/Ga2O3 diodes during continuous 10 A/650 V and 10 A/1.2kV inductive switching. The parametric shift is extracted by reconstructing a large-signal, dynamic I-V curve using the voltage and current waveforms recorded in each switching cycle. The junction shows a decrease in both turn-on voltage (Von) and differential on-resistance (RON-D ) by up to 0.25 V and 36%, respectively, after 107 switching cycles. Such shifts are found to be mitigated under higher switching voltage. Moreover, the circuit test data are compared to the parametric shifts under DC stress. While the parametric shifts under both tests can be characterized by a trapping/de-trapping time constant of ∼4200 s, the magnitude of parametric shifts are higher under the switching stress. The underlying physical mechanisms are discussed. These results provide key references to converter application of NiO/Ga2O3-based power devices and suggest the importance of switching-based methodology for device reliability evaluation.
