Abstract: As we look to move beyond traditional silicon semiconductor technology, wide-bandgap gallium nitride (GaN) micro/nanoelectronics have emerged as a promising alternative. GaN device technology is poised to revolutionize high-power and high-frequency applications. Additionally, GaN can unlock new application spaces for electronic systems that are currently constrained by the lack of robust semiconductor devices for harsh environments. While silicon technology is limited to moderate temperatures, GaN electronics have demonstrated a vast temperature range of operation from cryogenic to 1000°C. Devices that can achieve reliable operation under these conditions have applications in the space, energy and environment, automotive, and defense sectors, as well as quantum computing.
In this seminar, I will describe the design and microfabrication of indium aluminum nitride/gallium nitride (InAlN/GaN) high electron mobility transistors (HEMTs), which leverage a two-dimensional electron gas (2DEG) conducting channel. The lattice-matched InAlN/GaN heterostructure can enable co-fabrication of sensors and peripheral read-out circuitry on a single monolithically integrated chip. Advances in techniques to improve high temperature performance reliability in InAlN/GaN HEMTs, such as the development of novel contact metallization schemes and geometries, will be discussed. Recent compelling developments in high-temperature capable solid-state 2DEG devices and piezoelectric MEMS resonators up to 600°C in air for extended durations will be presented. This work has resulted in the first demonstration of an uncooled GaN device successfully operating in situ the harsh environmental conditions found on the surface of Venus with the goal of enabling long duration robotic planetary exploration. These contributions support the use of the GaN heterostructure and provide a road map for further maturing this semiconductor platform. Finally, I will conclude by discussing the exciting future landscape of GaN and other wide-bandgap microelectronics for the development of critical next generation “beyond silicon" technologies.
Biography: Dr. Savannah Eisner received the B.S. degree in electrical engineering from Villanova University in 2017, and the M.S. and Ph.D. degrees in electrical engineering from Stanford University in 2020 and 2023, respectively. Her dissertation research focused on the use of uncooled GaN transistors for extreme environment space applications. She is currently a postdoctoral researcher in the Extreme Environment Microsystems Laboratory (XLab) in the Department of Aeronautics and Astronautics at Stanford University. Her research interests include the design of wide-bandgap micro/nanoelectronic sensors and systems. Dr. Eisner was a National Science Foundation (NSF) Graduate Research Fellow and a Future Technical Leaders Fellow of the NSF engineering research center for power optimization and electro-thermal systems. She is the recipient an IEEE Aerospace Best Paper Award for her work on GaN microelectronics for future Venus surface missions.
