Wide Bandgap Material and Device Development

The purpose of the proposed research is to develop GaN molecular beam epitaxy on diamond substrates up to 3 inches in diameter. This unique substrate/epilayer combination will provide electronic materials suitable for high-power and opto-electronic devices without the commonly observed limitations due to the production of excess heat during device operation. The resulting devices will have built-in thermal heat spreading capability which should result in better performance and higher reliability. It will also have the capability of being extended to wafer sizes of 200mm or larger. This project will combine UC Berkeley's expertise in buffer layer development for GaN growth by MBE, advanced transmission electron microscopy techniques and state-of-the-art optical and electrical characterization, with unique diamond substrate growth and processing from sp3 and device reliability expertise and modeling capabilities at the Naval Postgraduate School. A precise substrate characterization and optimization for crystal orientation and grain size and the development of an optimized buffer layer on diamond are essential parts of this research project. The team will frequently exchange their results to optimize their respective deliverables such as buffer layer with GaN overgrowth for UC Berkeley, optimized diamond substrate characteristics for sp3, and adjusted device reliability model for NPS.