Thermally Hardened RF GaN HEMTs in Extreme Environments

Abstract

Traditional, room temperature electronics based on silicon has truly changed the world around us over the past 70+ years. However, many more applications still exist that are limited by the temperature performance of silicon devices (<250◦C). This area of high temperature (HT) electronics is an increasingly growing field with critical future applications in geothermal energy, space exploration, hypersonic aircraft, and deep gas/oil drilling, among others. Gallium Nitride (GaN) high electron mobility transistors (HEMTs) are especially well suited for high temperature electronic applications due to their low intrinsic carrier concentration and excellent electrical properties. Despite great progress in HT GaN technology, most demonstrations target logic or mixed-signal applications, and the performance of radio-frequency (RF) GaN devices remains lacking at high temperatures despite the critical need for wireless communication systems and high-speed electronics for these high-temperature applications. In this thesis, we investigate the physics of GaN HEMT devices at high temperatures and design RF transistors that demonstrate record performance at these temperatures.