High-Performance Al–Sn–Zn–O Thin-Film Transistor With a Quasi-Double-Channel Structure

We successfully fabricated high-performance Al–Sn–Zn–O thin-film transistors (ATZO TFTs) with a quasi-double-channel (QDC) structure on glass by radio-frequency magnetron sputtering. The bilayer ATZO films are fabricated with different oxygen partial pressures during the sputtering process. The structure of the top ATZO layer is optimized to improve OFF-state performances. With this QDC structure, the ATZO TFT demonstrates excellent electrical performances, including a low OFF-state current of 840 fA, an ON/OFF current ratio of
$1.08 \times 10^{9}$
, a steep threshold swing of 0.16 V/decade, a superior saturation mobility of 108.28 cm
$^{2}\text{V}^{-1}\text{s}^{-1}$
, and a threshold voltage of 2.09 V.