Single-Event Burnout Hardening of Power UMOSFETs With Integrated Schottky Diode

This paper presents 2-D numerical simulation results of single-event burnout (SEB) for hardened power U-shaped gate MOSFET (UMOSFET) with Schottky diode (SD-UMOSFET). In this device, a Schottky diode is integrated into every unit cell of power UMOSFETs. We find that the Schottky contact can leak off the generated holes caused by an ion´s impact, and the SEB threshold voltage can be improved. The hardened structure means the addition of an N buffer layer based on a power UMOSFET here. So, the 70 V hardened power SD-UMOSFET discussed in this paper contains a Schottky diode and an N buffer layer, which can work normally without affecting steady-state characteristics. The reverse recovery characteristic and SEB performance of hardened SD-UMOSFET are both enhanced effectively. The reverse recovery time decreases 49%, the reverse recovery current peak decreases 56%, and the softness factor increases more than 100% when the hardened SD-UMOSFET is compared with the standard UMOSFET. In addition, the SEB threshold voltage increases to 64 V, which is 91% of the rated breakdown voltage.