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

摘要

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.