Enhancement-mode AlGaN/GaN MOS-HEMT on silicon with ultrathin barrier and diluted KOH passivation

Enhancement-mode AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors with ultrathin barrier are demonstrated in this paper. By using the very slow recessed etching, 4-nm-thick AlGaN barrier is achieved with 3 nm Al
₂
O
₃
insulating layer. We also implement the diluted KOH to eliminate the surface damages during the dry etching process. The device with ultrathin barrier (4 nm AlGaN and 3 nm Al
₂
O
₃
) is characterized with high saturation current excessed 400 mA/mm with low subthreshold swing and + 0.12 V threshold voltage.