Analysis of Single Event Response and Hardening Methods in 1.2 kV SiC Power MOSFET With Multicell and Termination Structure

In this article, the single event response and hardening methods of 1.2 kV silicon carbide (SiC) power MOSFET with multicell and field limiting rings (FLRs) termination structure are investigated by using numerical simulations. Our studies reveal that the termination region is insensitive to single-event burnout (SEB) due to the floating state (no grounded contact hole). It can be found that the electric potential difference along the penetrating path is small. Thus, the Kirk effect could not occur. Conversely, at the cell region, the whole area is connected with the source contact hole, the Kirk effect happens unavoidably if the high bias voltage is applied, leading to a continuous current generation with a local hot spot. Meanwhile, it can be found that the intersection of the cell and termination region is the most sensitive area when the strike position is near the contact hole. In this situation, the huge carriers are generated by the avalanche multiplication behavior like in the cell region. Then, the current will flow along the surface region, resulting in a continual current generation with a local temperature rising. Furthermore, a new hardening technique with a shortened metal plate is proposed. Simulation results indicate that the new structure can alleviate the current accumulation at the intersection region, bringing a better SEB tolerance.