Device performance of AlGaN/GaN MOS-HEMTs using La2O3 high-k oxide gate insulator

AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs) using La₂O₃ as gate oxide by electron-beam evaporated have been investigated and compared with the regular HEMTs [1]. The La₂O₃ thin film achieved a good thermal stability after 200degC, 400degC and 600degC post-deposition annealing due to its high binding energy (835.7 eV) characteristics. Our measurements have shown that La₂O₃ MOS-HEMTs exhibiting the best characteristics, including the lowest gate leakage current, the largest gate voltage swing, and pulsed-mode operation. In addition, a negligible hysteresis voltage shift in the C-V curve can be improved significantly after high temperatures annealing.