Single event burnout in field plate termination for 4H–SiC Schottky barrier diodes

This paper presents the electro-thermal coupled simulation results of single event burnout (SEB) in field plate (FP) termination for 4H–SiC Schottky barrier diodes (SBDs). The heavy ion strike at the SiC/SiO₂/metal intersection is proved to be the worst case for SEB, and the catastrophic failure is related to the large current density and rapid heat accumulation at the SiC/SiO₂/metal intersection, because the high electric field at this region can induce strong localized avalanche multiplication of the heavy ion-induced carriers. Then, based on the failure mechanism analysis, we discuss the possible hardening techniques. The simulations show that introducing a buffer layer between the N⁻ epi-layer and the N⁺ substrate can effectively reduce the sensitivity of the device to heavy ion radiation, but we have to make a compromise between the SEB tolerance and the on-state resistance. Besides, the carrier lifetime control is proved to be a promising hardening technique. When the carrier lifetime in the N⁻ epi-layer is lower than a certain value, the SEB tolerance can be significantly improved without sacrificing the electrical performance of the device.