Effect of Post Treatment For Cu-Cr Source/Drain Electrodes on a-IGZO TFTs.

Shiben Hu,Lei Wang,Ruiqiang Tao,Rihui Yao,Xianzhe Liu,Zhiqiang Fang,Junbiao Peng,Yong Zeng,Honglong Ning,Zhengcao Li,Linfeng Lan,Fuxiang Huang,Miao Xu

doi:10.3390/ma9080623

Abstract

We report a high-performance amorphous Indium-Gallium-Zinc-Oxide (a-IGZO) thin-film transistor (TFT) with new copper-chromium (Cu-Cr) alloy source/drain electrodes. The TFT shows a high mobility of 39.4 cm·V·s a turn-on voltage of −0.8 V and a low subthreshold swing of 0.47 V/decade. Cu diffusion is suppressed because pre-annealing can protect a-IGZO from damage during the electrode sputtering and reduce the copper diffusion paths by making film denser. Due to the interaction of Cr with a-IGZO, the carrier concentration of a-IGZO, which is responsible for high mobility, rises.

Highlights

The growing demands of high resolution (≥8 K), fast frame rate (≥480 Hz) and large panel size (≥110 inch) for flat panel displays need a thin-film transistor (TFT) array with high mobility and low resistance-capacitance (RC) delay [1,2]
The transfer curves of TFTs with Cu-Cr electrodes were measured under the drain voltage of
EV) could be ascribable to Cr oxide. These results reveal that Cr diffused into the amorphous Indium-Gallium-Zinc-Oxide (a-IGZO) film during the post-annealing phase

Summary

Introduction

The growing demands of high resolution (≥8 K), fast frame rate (≥480 Hz) and large panel size (≥110 inch) for flat panel displays need a thin-film transistor (TFT) array with high mobility and low resistance-capacitance (RC) delay [1,2]. Commercial display panels can utilize amorphous Indium-Gallium-Zinc-Oxide (a-IGZO) thin-film transistors (TFTs) to meet the high mobility requirement [3]. Pure Cu films exhibit poor adhesion to many substrates, such as glass and SiO2 [9–11]. Mo to prevent copper diffusing into IGZO and enhance the adhesion strength [12–14]. These technologies will increase manufacturing cost and difficulty of patterning because the etch rate of Cu and barrier layer metal (Ta, Ti, Mo, etc.) have an impact. Cu-Cr film exhibits good adhesion with glass

Experiments

Results and Discussion

Conclusions