Development of 2D and 3D transient electro-thermal computational models to predict the radiation failures in SiC-based Schottky diodes and power field-effect transistors (FETs)

The overarching goal of the proposed research in this NASA ESI project is to advance the understanding of failure mechanism in silicon carbide (SiC) power devices subject to heavy ion radiation, and provide the guidelines to design and fabricate SiC-based power devices with higher resistance to radiation single-event effects (SEEs). High voltage (HV) power devices based on SiC semiconductor material may offer revolutionary transformations for future NASA space missions, due to the roughly three-fold increase in bandgap of SiC material over traditional silicon (Si) material. The wide bandgap feature enables SiC power devices to operate at higher voltages, temperatures, and switching frequencies with greater efficiencies compared to existing Si devices. However, the unique space environment presents a great challenge to the device performance and reliability. To safely deploy SiC power devices for space missions, one has to first answer the question of how devices survive from the harsh radiation environment in space. Fundamental research into the radiation susceptibility and failure mechanisms of SiC power devices is necessary. An approach that combined computation and experiment efforts has been pursued and the project goal is realized by (1) developing physics-based 3D transient electro-thermal computational models to predict radiation failures in vertical SiC-based power devices subject to heavy-ion radiation, (2) validating the developed models via comparisons with testing and experimentation of SiC Schottky diodes and metal–oxide–semiconductor field-effect transistors (MOSFETs), and (3) optimizing Schottky diodes and MOSFET designs for radiation resistance by simulations based on the developed/validated models. Significant achievements have been accomplished over the four-year project period. The accomplishments consist of fundamental research to elucidate device failure mechanisms, computation model development and validation to realize predictive capabilities, and innovative engineering designs to advance the state of the art. Most significantly, the project has developed rad-hardened SiC Schottky diode and MOSFET designs that can survive Single Event Burnout (SEB) at the operation voltage of 1.2kV while the baseline on-state performance is still comparable to current 1.2kV-rated commercial SiC power devices. The rad-hardened designs will be transitioned to industry for further fabrication and test through the NASA SBIR/STTR program.