High-Performance and Flexible Neodymium-Doped Indium-Zinc-Oxide Thin-Film Transistor With All Copper Alloy Electrodes

In this paper, we examine the possibility of using homogeneous and monolayer Cu-0.08 wt. % Cr-0.05 wt.% Zr (CuCrZr) ternary alloy film as both bottom-gate and source/drain (S/D) electrodes for flexible neodymium-doped indium-zinc-oxide (NdIZO) thin-film transistor (TFT) applications. Under the optimized sputtering parameters (250 W & 1.4 mtorr) and annealing process (380 °C & text4 h, N
₂
atmosphere), the resistivity of the alloy film is as low as 2.47 μ·cm (300 nm) and the adhesion strength to polyimide (PI) substrate reaches 4 B-5 B level, which is competent for high-performance flexible display. As a result, the flexible NdIZO-TFTs with all-CuCrZr electrodes operate in enhancement mode with both high electrical performance (μ
_FE
of 32.1 cm
²
/V·s, I
_on
/I
_off
of 10
⁷
, V
_th
of 0.42 V, SS of 0.16 V/decade, RC-norm of 84.5Ω·cm and Vth of -0.28 V/+2.46 V under ±1MV/cm positive/negative bias stress (NBS/PBS) for 5400 s) and good mechanical flexible performance ( V th of only -0.32 V/-0.29 V under r-2.5mm-static and 10K-times dynamic bending test).