Thermal Assessment of AlGaN/GaN MOS-HEMTs on Si Substrate Using Gd2O3 as Gate Dielectric

Thermal stability of AlGaN/GaN metal–oxide–semiconductor high-electron mobility transistors (MOS-HEMTs) and diodes using Gd2O3is investigated by means of different thermal tests. DC and pulsedI–Vcharacterization of the devices before and after the processes shows that the devices with Gd2O3dielectric layer have more than three orders of magnitude lower leakage current, higher ON/OFF ratio of about10⁸, and better thermal stability after the long thermal storage test (500 °C, 8 days) compared with conventional devices. In addition, no hysteresis and a stable threshold voltage were observed after a short thermal test (500 °C, 5 min) in the MOS diodes, in good agreement with the lower trapping effects observed in the MOS-HEMTs.