Physical Model for SiC Power Device Heavy-Ion Burnout Based on Pre-Strike Depletion Capacitance Energy Storage

Abstract

An analytical model for predicting high-linear energy transfer (LET), normal incidence single-event burnout (SEB) voltage in SiC power devices is presented. The concept of critical energy stored in the drain-body depletion region and released by the passing ion is introduced and used to derive an expression for high-LET, normal incidence (worst case) SEB voltage that depends only on epitaxial layer doping. The model is validated by experimental data ranging from 1200 to 4500 V. The relative independence of high-LET, normal incidence SEB, and epitaxial layer thickness is demonstrated experimentally and is supported by the model. The 900 V SEB voltage devices are experimentally demonstrated. The derating factor for SiC devices as a function of voltage is explained with the model. A lumped RC model is used to gain insights into SEB for both low- and high-LET ions. Low-LET SEB response appears consistent with power-density models and thermal spike effects. High-LET SEB response is qualitatively similar to single-event gate rupture (SEGR), with the depletion capacitance as the energy storage element. Implications for SEB-optimized SiC power devices are described.