Effect of High Temperature RF Stress on the Trapping Behavior of Carbon Doped AlN/GaN/AlGaN HEMTs

This study investigates the impact of short-term high-temperature operating life (HTOL) reliability testing on the trapping behavior and power performance of carbon-doped AlN/GaN/AlGaN High Electron Mobility Transistors (HEMTs). HTOL stress can lead to significant degradation in key performance metrics, including output power (Pout) and power-added efficiency (PAE), primarily due to increased current collapse and knee walkout. Transmission Electron Microscopy (TEM) analysis revealed the formation of voids at the gate foot on the drain side, indicating physical damage. Drain current transient spectroscopy (DCT) revealed post-stress changes in trap dynamics, including the emergence of a secondary emission process (E2). Further analysis attributed E2 to the overlap of enhanced emission from a field-dependent deep-level trap (E1, activation energy ~0.7 eV) and a stress-induced increased density of traps with distributed energy level.