Investigation of direct inkjet-printed versus spin-coated ZrO2 for sputter IGZO thin film transistor

Wei Cai; Honglong Ning; Zhennan Zhu; Jinglin Wei; Shangxiong Zhou; Rihui Yao; Zhiqiang Fang; Xiuqi Huang; Xubing Lu; Junbiao Peng

doi:10.1186/s11671-019-2905-2

Investigation of direct inkjet-printed versus spin-coated ZrO₂ for sputter IGZO thin film transistor

Nanoscale Res Lett. 2019 Mar 5;14(1):80. doi: 10.1186/s11671-019-2905-2.

Authors

Wei Cai¹, Honglong Ning², Zhennan Zhu¹, Jinglin Wei¹, Shangxiong Zhou¹, Rihui Yao³, Zhiqiang Fang⁴, Xiuqi Huang⁵, Xubing Lu⁶, Junbiao Peng¹

Affiliations

¹ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China.
² Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China. ninghl@scut.edu.cn.
³ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China. yaorihui@scut.edu.cn.
⁴ State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, China.
⁵ Gu'an New Industry Demonstration Zone, Langfang, 065500, Hebei, People's Republic of China.
⁶ Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, China.

Abstract

In this work, a low leakage current ZrO₂ was fabricated for sputter indium gallium zinc oxide (IGZO) thin-film transistor using direct inkjet-printing technology. Spin-coated and direct inkjet-printed ZrO₂ were prepared to investigate the film formation process and electrical performance for different process. Homogeneous ZrO₂ films were observed through the high-resolution TEM images. The chemical structure of ZrO₂ films were investigated by XPS measurements. The inkjet-printed ZrO₂ layer upon IGZO showed a superior performance on mobility and off state current, but a large V_th shift under positive bias stress. As a result, the TFT device based on inkjet-printed ZrO₂ exhibited a saturation mobility of 12.4 cm²/Vs, an I_on/I_off ratio of 10⁶, a turn on voltage of 0 V and a 1.4-V V_th shift after 1-h PBS strain. Higher density films with less oxygen vacancy were responsible for low off state current for the printed ZrO₂ device. The mechanism of deteriorated performance on PBS test can be ascribed to the In-rich region formed at the back channel which easily absorbs H₂O and oxygen. The absorbed H₂O and oxygen capture electrons under positive bias stress, serving as acceptors in TFT device. This work demonstrates the film formation process of direct inkjet-printed and spin-coated oxide films and reveals the potential of direct inkjet-printed oxide dielectric in high-performance oxide TFT device.

Keywords: Bias stress stability; Direct inkjet printing; Interface; Oxide dielectric.

Grants and funding

2016B090907001/Guangdong Science and Technology Project