Experiment and analysis of repetitive avalanche low-current stress on 4H-SiC power devices

As a kind of 4H-SiC power device, the junction barrier Schottky (JBS) rectifiers, only containing the transition p + implantation region at the edge of the active region in the termination region, are adopted and fabricated to analyze the effect of the repetitive avalanche low-current stress on the SiO2/4H-SiC interfacial state of the devices. The breakdown voltage (BV) of the device shifts after the repetitive avalanche current stress, which results from the electron injects into the SiO2/4H-SiC interface and trapped by the interface states. Meanwhile, there is a tradeoff between the quantities of the trapped and de-trapped electrons by the SiO2/4H-SiC interface states when the BV reaches its saturated value. The junction temperature, total amount of carriers generated in the single avalanche event and repetitive total avalanche energy, affected by the pulse period (T), pulse number and turn on period (D), are the key factors that affect the level of the BV shift.