Comparative Operation of Ultra-Wide Bandgap Devices for Voltage/Power Conversion

Ultra-Wide-Bandgap (UWBG) semiconductors hold great promise for future power conversion applications, especially for incorporation at grid-level currents and voltages (10s-100s of kV,100s of A). Figures of Merit (FOMs) are often used as a first means to understand the impact of semiconductor material parameters on power semiconductor performance, and, in particular, the Unipolar (or Baliga) FOM is often cited for this purpose. However, the use of UWBG materials in a given application requires the fabrication of devices followed by system insertion. While the benefit of UWBG incorporation in power converters should roughly scale with the UFOM, there are several factors of importance for UWBG incorporation in switching power converters that are not explicitly included in UFOM-type calculations including switching behavior, incomplete ionization, mobility, and temperature dependence.<br/><br/>This talk will give an overview of work under the Ultra Materials for a Resilient, Smart Electricity Grid, a Department of Energy Basic Energy Sciences Energy Frontier Research Center, dedicated to evaluating the impact of UWBG materials in grid-level power electronic converters. Toolsets and modeling efforts will be introduced to evaluate how material characteristics of UWBG semiconductors percolate up to system-level improvements, especially regarding power dissipation for different material systems and device types in switching power converters. An optimization technique for two- and three-terminal devices will be introduced that calculates the minimum power dissipation in a switching power converter for a given system operational regime (reverse voltage, forward current density, frequency, duty cycle, and temperature), thereby allowing utilization of the optimal material/device combination for that application. A variety of UWBG device types and materials systems will be directly compared, e.g. diamond, gallium oxide, and aluminum nitride. This gives an overall roadmap for materials systems and device structures that can be utilized to target UWBGs to specific application areas.