Characterization and Mitigation of Radiation and High Temperature Effects in SiC Power Electronics

Future NASA science and exploration missions require significant performance improvements over the state-of-the-art in Power Management and Distribution (PMAD) systems. Space qualified, high voltage power electronics can lead to higher efficiency and reduced mass at the spacecraft system architecture level, and serve as an enabling technology for operational concepts such as solar electric propulsion. Silicon carbide (SiC) is a robust technology with superior electronic properties for power applications. SiC devices offer higher temperature operation, lower on-resistance, higher breakdown voltages, and higher power conversion efficiency than silicon devices. However, high vulnerability to heavy-ion induced degradation and catastrophic failure has precluded this technology from space PMAD applications. Importantly, physical mechanisms for this vulnerability are not well understood, resulting in the inability to develop radiation hardened SiC devices. CFDRC, in collaboration with Vanderbilt University and Wolfspeed, is applying a coupled experimental and physics-based modeling approach to address this challenge. In Phase I, we performed electrical and heavy ion tests on 1200V Wolfspeed SiC JBS diodes to generate response data, and performed TCAD simulations to investigate diode sensitivity to design parameters and analyze electro-thermal mechanisms behind measured response. In Phase II, we will develop further insight into physical mechanisms in the diodes via development and application of advanced physics models. We will parametrically analyze design features to identify promising hardness solutions, which will then be fabricated and experimentally characterized. We will also perform heavy-ion testing of 1200V SiC MOSFETs and apply simulations for insights into governing mechanisms (to be further developed in follow on work). Direct participation by Wolfspeed in Phase II and beyond will ensure space-qualified, SiC power devices for NASA applications.