High-temperature operation of Al 2 O 3 /Ga 2 O 3 bi-layer gate stack GaN MOS-HEMT up to 450 °C with suppressed gate leakage

In this work, we report the reduced gate leakage current by using aluminum oxide (Al 2 O 3 ) and gallium oxide (Ga 2 O 3 ) as a bi-layer gate stack for GaN MOS-HEMT on a silicon substrate up to 450 °C. The bi-layer gate stack MOS-HEMTs suppressed the gate leakage by more than four orders of magnitude compared to only Al 2 O 3 -based GaN MOS-HEMT at 450 °C. The low gate leakage current is attributed to the reduced oxygen vacancies present in the Ga 2 O 3 layer, which effectively impede the conduction path of the Poole-Frenkel emission at high temperatures, thereby enhancing the overall performance of GaN HEMTs.