Low Interface Trap Densities and Enhanced Performance of AlGaN/GaN MOS High- Electron Mobility Transistors Using Thermal Oxidized Y2O3 Interlayer

AlGaN/GaN metal-oxide-semiconductor high-electron mobility transistors (MOS-HEMTs) with Y₂O₃ interlayer have been investigated to improve the interface quality. With the HfO₂/Y₂O₃ stack gate dielectrics, the devices show a saturated drain current density of up to ~943 mA/mm. Meanwhile, the pulsed Id-Vg measurement indicates interface traps are as low as 5.2 × 10¹¹ cm^-2, and the pulsed-IV measurement exhibits great resistance to current collapse. Furthermore, the devices also present good reliability under negative bias stress. Therefore, the interface engineering based on Y₂O₃ has a potential to open up a new avenue to high-performance AlGaN/GaN MOS-HEMTs.