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

Abstract

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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.08 \times 10^{9}$ </tex-math></inline-formula> , a steep threshold swing of 0.16 V/decade, a superior saturation mobility of 108.28 cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{2}\text{V}^{-1}\text{s}^{-1}$ </tex-math></inline-formula> , and a threshold voltage of 2.09 V.