Hot Electron stress on unpassivated GaN/AlGaN/GaN HEMTs

GaN-based high electron mobility transistors (HEMTs) are nowadays of major interest due to their high frequency and high-power performances. Although power densities up to 32 W/mm have been recently demonstrated (1), reliability is still one of the issue that has to be addressed in order to move toward commercially available devices (2). In this paper, we present a detailed characterization of preand after-hot-electron-stress performance of unpassivated GaN/AlGaN/GaN HEMTs on SiC substrates, allowing the main degradation modes to be identified and possible underlying physical mechanisms to be probed.