Research of Single-Event Burnout in Floating Field Ring Termination of Power MOSFETs

This paper presents the 2-D numerical simulation results of the single-event burnout (SEB) in the floating field ring (FFR) termination of a power MOSFET for the first time. We investigate the SEB triggering mechanism and SEB performance based on a 140-V typical FFR termination, and find that the structure is sensitive to SEB because of a sharp temperature rise appearing at the p
⁺
base/n-drift junction. A 140-V hardened FFR termination (an n-type buffer layer is added between the epitaxial layer and substrate layer) is also studied in this paper that can demonstrate much better SEB performance without sacrificing the basic characteristics compared to the standard one. In addition, the hardening mechanism is explained, and the performances of the hardened structures with different buffer layer thickness are discussed. As a result, the safe operating area can reach the value of the breakdown voltage when the thickness achieves or exceeds
$3~\mu \text{m}$
.