GaN-based Power Device Manufacturing for Automotive Applications Utilizing Production MBE Technology

Gallium nitride-based electronics offer significant potential advantages for automotive onboard electronics but remain unqualified for vehicle use at present. The performance of gallium nitride devices is superior to competing silicon switches in that they offer significantly smaller on-state resistance and higher switching frequency. The resulting performance benefits include increased efficiencies and reduced passive device requirements for power inverter applications. However, gallium nitride-based power electronics are not yet fully qualified in terms of vehicle performance requirements and their high cost compared to Si remains a barrier to adoption. This Phase I project will address the qualification of gallium nitride-based devices for automotive requirements. The work will be performed based on a production molecular beam epitaxy platform utilizing a hybrid ammonia and nitrogen-plasma source approach. The hybrid approach gives greater flexibility in growth rate and growth condition leading to materials optimized in critical layer quality the overall layer uniformity. For electric vehicle applications, gallium nitride on silicon devices with breakdown voltages exceeding 600V have been demonstrated. In order to increase current carrying capability to near 100A, a well-controlled dopant profile and interface abruptness are critical and achievable based on molecular beam epitaxy growth capabilities. An additional issue to be addressed is reduction of cost towards parity with silicon switch technology. By employing a production platform from the start, we will have the ability to scale up epitaxial wafer diameter beyond 100 mm. Production growth systems can already handle up to 200 mm size substrate for power devices. The use of large diameter silicon substrate is a direct path toward cost reduction through increased device yield and taking advantage of the existing silicon-based processing infrastructure. Prototype large diameter gallium nitride epitaxial materials for power applications shall be demonstrated during the Phase I. Evaluation efforts shall include device/materials characteristics such as uniformity, transistor performance and device reliability. Results from these power devices shall be benchmarked to currently available silicon-based technology and a viable business model for commercialization developed. Device design, process, and testing shall be performed in collaboration with team members from academia and industry. The prosed technological innovations would encourage the further proliferation of electric vehicles. Wide spread vehicle electrification would result in the decrease of carbon-based emissions from the replacement of the internal combustion engine and potentially impact global climate trends. Further, improved electrification can transform mobility and have the potential impact society broadly. Beyond the technical innovations and applications of this technology, this project would have beneficial societal, scientific, and educational impacts such as on advancing science, creating high skill/high tech jobs in the US, hiring highly educated people, collaboration with academia, and creating a technology that could be used for many future scientific applications.