Low interface state density in Al₂O₃/n-GaN MOS capacitors with rapid deposition of Al₂O₃ gate insulator fabricated via mist-CVD

Abstract This study highlights the potential of mist chemical vapor deposition (mist-CVD) as an eco-friendly, cost-effective gate insulator deposition method for GaN-based metal-oxide-semiconductor (MOS) devices. We deposited an Al 2 O 3 gate insulator on homoepitaxial n-GaN structures via mist-CVD. We found that mist-CVD achieved a deposition rate of 30 nm min −1 . From an admittance analysis, quantitative characterizations confirmed low interface state density at the Al 2 O 3 /n-GaN interface near the conduction band edge, in the range of 10 10 cm −2 eV −1 . These findings demonstrate that mist-CVD exhibits performance comparable to the conventional deposition method, atomic layer deposition, highlighting the potential of mist-CVD for GaN-based MOS device applications.