Effect of High Temperature on the Performance of AlGaN/GaN T-Gate High-Electron Mobility Transistors With ~140-nm Gate Length

High temperature (HT) electronics applications will require the development of a broad range of devices made using different materials. Among these devices, high-electron mobility transistors (HEMTs) made with GaN and its alloys are attractive for high-power radio frequency (RF) applications. In this manuscript, we tested AlGaN/GaN HEMT devices having ~140-nm gate length at different temperatures up to 500 °C. Devices were fabricated using Air Force Research Laboratory's (AFRL's) 140-nm {T} -gate process technology. The performance degradation measured in different devices was analyzed by considering changes in different device parameters and by using appropriate device physics. Cross-sectional materials characterization using scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) was performed to understand the origin of performance degradation. This understanding will allow us to design a sub- \mu \text{m} GaN-based process technology compatible with HT RF applications.