SiC Semiconductor Switches for Klystron Modulators

The extremely challenging speed (>3 MHz) and voltage (>5 kV) specifications of Damping Ring (DR) Kicker Modulators for the planned International Linear Collider (ILC) require the development of revolutionary new semiconductor switch technology. In addition, the robustness and reliability of capacitor charging circuits used in 140 kV Marx bank ILC Klystron modulators would be enhanced significantly if sub-50 nanosecond, 12 kV semiconductor switches were available. This project will develop technology to meet these specifications by exploiting the superior electrical and thermal properties of the emerging power semiconductor material of choice, silicon carbide. In Phase I, analytical and two-dimensional simulations were conducted to accurately model a novel SiC device, the SuperJFET, which was invented recently. Test structures were fabricated in a commercial semiconductor foundry to demonstrate critical fabrication steps, such as reactive ion etching and passivation. Fully isolated power modules were designed and fabricated to enable the reliable packaging of 12 kV SiC devices. In Phase II, five batches of SiC SuperJFET devices, with successively increasing voltage capabilities, will be designed and fabricated. A high volume silicon carbide foundry will be designed to allow the economical production of SuperJFET devices. Commercial Applications and Other Benefits as described by the awardee: These high voltage devices should have applications for utilities, where these advanced high power electronic components would enable precise reactive compensation, control, and tuning of all circuits, promising unprecedented increases in the efficiency and cost-effectiveness of the electricity infrastructure. Other applications include use in accelerators for cancer treatment, hospital waste sterilization, and food irradiation. Finally, the devices should be suitable for the solid state power conditioning systems used in high energy weapon systems.