Tunability of p- and n-channel TiOx thin film transistors

Wu-Chang Peng; Yao-Ching Chen; Ju-Liang He; Sin-Liang Ou; Ray-Hua Horng; Dong-Sing Wuu

doi:10.1038/s41598-018-27598-5

Tunability of p- and n-channel TiO_x thin film transistors

Sci Rep. 2018 Jun 18;8(1):9255. doi: 10.1038/s41598-018-27598-5.

Authors

Wu-Chang Peng¹, Yao-Ching Chen¹, Ju-Liang He², Sin-Liang Ou³, Ray-Hua Horng⁴, Dong-Sing Wuu^{5

6}

Affiliations

¹ Department of Materials Science and Engineering, National Chung Hsing University, No. 145, Xingda Road, Taichung, 40227, Taiwan.
² Department of Materials Science and Engineering, Feng Chia University, No. 100, Wenhwa Road, Taichung, 40724, Taiwan.
³ Department of Materials Science and Engineering, Da-Yeh University, No. 168, University Road, Changhua, 51591, Taiwan.
⁴ Institute of Electronics, National Chiao Tung University, No. 1001, University Road, Hsinchu, 30010, Taiwan.
⁵ Department of Materials Science and Engineering, National Chung Hsing University, No. 145, Xingda Road, Taichung, 40227, Taiwan. dsw@nchu.edu.tw.
⁶ Innovation and Development Center of Sustainable Agriculture (IDCSA), National Chung Hsing University, No. 145, Xingda Road, Taichung, 40227, Taiwan. dsw@nchu.edu.tw.

Abstract

To acquire device-quality TiO_x films usually needs high-temperature growth or additional post-thermal treatment. However, both processes make it very difficult to form the p-type TiO_x even under oxygen-poor growth condition. With the aid of high energy generated by high power impulse magnetron sputtering (HIPIMS), a highly stable p-type TiO_x film with good quality can be achieved. In this research, by varying the oxygen flow rate, p-type γ-TiO and n-type TiO₂ films were both prepared by HIPIMS. Furthermore, p- and n-type thin film transistors employing γ-TiO and TiO₂ as channel layers possess the field-effect carrier mobilities of 0.2 and 0.7 cm²/Vs, while their on/off current ratios are 1.7 × 10⁴ and 2.5 × 10⁵, respectively. The first presented p-type γ-TiO TFT is a major breakthrough for fabricating the TiO_x-based p-n combinational devices. Additionally, our work also confirms HIPIMS offers the possibility of growing both p- and n-type conductive oxides, significantly expanding the practical usage of this technique.