Single Event Effect on SiC MOSFETs With Junction Barrier Schottky Diode Structures

This article investigates the single event effects (SEEs) in SiC MOSFETs integrated with a junction barrier diode [MOSFET integrated with JBS structure (JMOS)]. During irradiation experiments, JMOS exhibited drain-to-source leakage current degradation and ultimately experienced burnout as the drain voltage increased. However, the gate leakage current remained almost unchanged throughout the irradiation process but increased under the post-irradiation gate stress (PIGS) test. The anatomical analysis demonstrated that the deformation of ohmic contact metal and the generation of gate oxide voids in the active region were the causes of failures. By employing Sentaurus technical computer-aided design (TCAD) simulation tools, hot spots were concentrated at ohmic metal corners when the heavy ions struck in the middle of the JFET region in the junction barrier Schottky diode (JBS) structure. In addition, a remarkable increase in the maximum oxide electric field strength was observed when the injection position was located in the middle of the JFET region, which led to the potential damage of the oxide layer, resulting in the final failure under the PIGS test. Therefore, different from conventional SiC JBS and MOSFET devices, JMOS exhibited a unique failure mechanism arising from the synergistic interaction between both JBS and MOSFET cell structures.