Large Area SiC GTO Thyristor Development Widebandgap High Voltage High Frequency Switches

The extremely challenging speed and voltage specifications of converter circuits used to attach renewable energy sources and energy storage elements to the power grid require the development of new semiconductor switch technology. In addition, the robustness and reliability of energy storage power processing circuits used in conventional power grid systems are enhanced significantly with the availability of sub-microsecond Thyristors. The voltage specification achieved is beyond the theoretical limit that can be achieved with contemporary Silicon technology, is within the room temperature corona limit, and is compatible with commercially available capacitors. These challenging specifications are enabled by fully exploiting the superior electrical and thermal properties of the emerging power semiconductor material of choice: Silicon Carbide (SiC). In the Phase I, a nearly-ideal blocking voltage SiC Gate Turn Off (GTO) Thyristor was found to offer the best solution for the challenging requirements. Extensive simulations were conducted to model SiC GTO Thyristor devices and their performance was verified. Test structures were fabricated and power-packaging technology was explored. In the Phase II project, five batches of SiC GTO Thyristor devices will be designed and fabricated with successively increasing voltage and current capabilities to meet the program objectives. Commercial Applications and other Benefits as described by the awardee: Government and commercial markets that have been identified include electric power utilities, medical imaging and cancer treatment, and industrial systems for food irradiation and hospital waste sterilization.