SiC Mosfet with Radiation-Resistant Gate Oxide Performance to 600V

Single-event burnout (SEB) and gate rupturenbsp;occur when high-energy ions strike SiC MOSFET devices in the OFF state. Heavy ion radiation caused irreversible damage (possibly owing to SEGR) at biases below 10% and catastrophic failure at biases below 40% of their nominal blocking voltage in commercial SiC power devices. Commercial SiC MOSFETs degrade fornbsp;latent gate leakage even at 50V drain-to-source voltage (VDS). Heavy ion collisions produce high-concentration electron-hole pairs that cause gate damage. In an n-channel MOSFET, electric field produced by the positive drain bias causes the generated holes and electrons to flow in opposite directions. The gate oxide interface quot;accumulatesquot; and quot;leaksquot; holes toward the source contact. When the oxide#39;s electric field surpasses a threshold, it breaks down.SCDevice has designed a SiC MOSFET device with a P+ shield layer that prevents SEB by maintaining temperatures well below the sublimation point of SiC (2973deg;K) and by diverting the holes away from the gate oxide. Remarkably, our simulations show that 600V SEB performance can be achieved with only a P+ shield layer. Simulations reveal that when subjected to an ion strike with a LET of 40 MeV-cm2/mg, our devices biased at VDS=600V show temperature rise under 750deg;K and electric field of less than 4.0MV/cm in the gate oxide. Our findings demonstrate more than sixfold increase in the device bias before gate degradation may occur, potentially enabling the use of SiC MOSFET in space applications. We intend to manufacture and market SiC MOSFET for space applications. Our innovation can be applied to Si MOSFET devices to enhance the radiation performance. During phase-II, SCDevice will design and fabricate the MOSFET, radiation test, use the data to calibrate simulation models, re-design and fabricate lot-2 and complete radiation testing to verify performance. During technology development and validation, SCDevice will identify and address customer needs and pain points.