High-Performance Al–Sn–Zn–In–O Thin-Film Transistors: Impact of Passivation Layer on Device Stability

We fabricated high-performance thin-film transistors (TFTs) with an amorphous-Al-Sn-Zn-In-O (a-AT-ZIO) channel deposited by cosputtering using a dual Al-Zn-O and In-Sn-O target. The fabricated AT-ZIO TFTs, which feature a bottom-gate and bottom-contact configuration, exhibited a high field-effect mobility of 31.9 cm
²
/V·s, an excellent subthreshold gate swing of 0.07 V/decade, and a high
I

_on/off
ratio of >10
⁹
, even below the process temperature of 250°C. In addition, we demonstrated that the temperature and bias-induced stability of the bottom-gate TFT structure can significantly be improved by adopting a suitable passivation layer of atomic-layer-deposition-derived Al
₂
O
₃
thin film.