Ultra-widebandgap Ga2O3 power devices for next generation power electronics

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Power electronics, in contrast to the electronics in laptops and smart phones, controls and handles the flow of power. Power electronics is the enabling technology for integration of renewable energy sources such as wind, solar, and geothermal to the future energy grid for both energy and environmental security. In addition, power electronics has a critical role in power efficient electric and hybrid cars. At the heart of power electronics is a power transistor that switches the power on and off. Energy is lost as heat during this process. Widebandgap semiconductors enable new power electronics technology that can significantly reduce the energy losses than the present silicon based technology. A new widebandgap semiconductor, gallium oxide, is investigated here for efficient power electronics. The fundamental properties of this novel widebandgap semiconductor will be explored using advanced scientific methodology. Studies will also be carried out to develop a technology to change the electrical conductivity of the semiconductor, which is essential to building the power transistor. These studies will also increase the understanding of the widebandgap semiconductor that have potential application in other fields. In addition to the materials properties, electrical testing of the transistors will be carried out to evaluate the speed of the power transistors.This project will position US at the forefront of power electronics innovation and propel the recent continued growth of the power electronics industry with positive outcomes on the US economy. The environmental and energy security of US will be enhanced due to high efficiency in switching and reduced greenhouse gases. The research opportunity given to undergraduate and graduate students will help build the skills of the future workforce for knowledge based economy and maintain the economic competitiveness of the US. The research effort will be integrated with educational outreach activities for undergraduates, high-school students and under-represented students in science and engineering. It will increase the participation of underrepresented minority and women in the field of science and engineering enhancing US competitiveness in science and engineering.The objectives of the proposal is to develop a fundamental understating of the materials properties of the emerging gallium oxide widebandgap semiconductor and develop a high voltage power transistor. N-type doping and isolation doping by ion-implantation will be investigated. The doped films will be characterized by advanced materials characterization techniques including secondary ion microscopy (SIMS), Rutherford backscattering (RBS) and also by electrical test structures. The doping technology enables the engineering of the electric field profile in the power transistor to increase the breakdown voltage. In addition the electron transport properties and interface electrical properties will be characterized. Building upon the fundamental studies, high voltage power transistors will be fabricated. The switching speed of the power transistors will be characterized by double pulse method. These studies will be advance the understanding of the widebandgap semiconductor properties. In addition, an accurate comparison of the technology with other widebandgap semiconductors can be made.