Time-Periodic Avalanche Breakdown at the Edge Termination of Power Devices

We show that the "variation of lateral doping" (VLD) edge termination technique (Fig. 1) exhibits a surprisingly high robustness in the avalanche regime. This is the consequence of a self-limiting time-periodic current filamentation mechanism, which prevents the VLD structure from being destroyed, in contrast to stable stationary current filaments staying permanently at the same location as it is observed in the commonly used "junction termination extension" (JTE) structure (Fig. 1). Our findings are based on detailed numerical device simulations, which are corroborated by measured data from test devices.