Electrical and reliability performances of stacked HfO2/Al2O3 MOS-HEMTs

We propose and demonstrate an Al_0.27Ga_0.73N/GaN metal-oxide-semiconductor high electron mobility transistor (MOS-HEMT) with the HfO₂/Al₂O₃ dual gate dielectrics by using sputtering/hydrogen peroxide (H₂O₂) oxidation techniques. The present HfO₂/Al₂O₃ dual gate dielectrics MOS-HEMT can combine the advantages of both dielectric properties and the device performances such as output current, device gain, off/on-state breakdown, pulsed I-V, high-frequency, and reliability performances under on-state stress are investigated with respect to Schottky-gate HEMT and single Al₂O₃ gate dielectric MOS-HEMT. In addition, the present MOS-HEMT shows the superior improvements of DC/RF performances, the RF current collapse, and the reliability characteristics as compared with other devices in this work.