SCALE Mechanics of Rapid Threshold-Voltage Recovery in TID-Irradiated SiC Power MOSFETs

Zachary Stone, a graduate student at Vanderbilt University, presented at the Vanderbilt Seminar Series.

Silicon carbide (SiC) Power MOSFETs are increasingly important for high-voltage, high-temperature, and high-frequency aerospace and defense applications, but their relatively thick gate oxides and sensitive SiC/SiO2 interfaces make them particularly vulnerable to total ionizing dose (TID) degradation. This research investigates the use of positive high electric field stress (PHEFS) as a rapid electrical recovery technique for TID-induced Vth degradation in commercial SiC power MOSFETs. The results show that Fowler-Nordheim electron injection via PHEFS can restore most of the TID-induced Vth degradation on time scales of seconds to minutes and remain highly repeatable during cumulative irradiation-recovery cycling experiments. However, recovery is limited by device-dependent electric field conditions where competing mechanisms such as impact-ionization-assisted hole trapping reduce net recovery.