Impact of Gate Switching Instability in SiC MOSFETs Application Performance Degradation During Hard Switching Conversion

In addition to the well-known bias temperature instability (BTI) phenomena, recently, it has been revealed that SiC MOSFETs show another instability during high-frequency repetitive switching between $\mathbf{V}_{\mathbf{G S}(\mathrm{L})}$ and $\mathbf{V}_{G S(H)}$, referred to as gate-switching instability (GSI). This study examines the increase in dynamic losses and junction temperature caused by GSI induced $\mathrm{V}_{\mathrm{GS}(\mathrm{th})}$ drift, which are key performance parameters in the application. A new methodology featuring double pulse tests was applied at each measurement readout. Lookup table (LUT) models were created for pristine values and after 1000 hours of stress. The results highlighted the significance of the degradation mechanism through its impact on hard-switching applications with high-switching frequency. Therefore ruggedness to GSI plays a pivotal role in the long-term reliable operation of SiC MOSFET devices to ensure durable and efficient power conversion systems.