Solution-Processed Silicon Doped Tin Oxide Thin Films and Thin-Film Transistors Based on Tetraethyl Orthosilicate

Ziyan He; Xu Zhang; Xiaoqin Wei; Dongxiang Luo; Honglong Ning; Qiannan Ye; Renxu Wu; Yao Guo; Rihui Yao; Junbiao Peng

doi:10.3390/membranes12060590

Solution-Processed Silicon Doped Tin Oxide Thin Films and Thin-Film Transistors Based on Tetraethyl Orthosilicate

Membranes (Basel). 2022 Jun 1;12(6):590. doi: 10.3390/membranes12060590.

Authors

Ziyan He¹, Xu Zhang¹, Xiaoqin Wei², Dongxiang Luo³, Honglong Ning¹, Qiannan Ye¹, Renxu Wu¹, Yao Guo¹, Rihui Yao¹, Junbiao Peng¹

Affiliations

¹ State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, China.
² Southwest Institute of Technology and Engineering, Chongqing 400039, China.
³ Guangzhou Key Laboratory for Clean Energy and Materials, Huangpu Hydrogen Innovation Center, School of Chemistry and Chemical Engineering, Institute of Clean Energy and Materials, Guangzhou University, Guangzhou 510006, China.

Abstract

Recently, tin oxide (SnO₂) has been the preferred thin film material for semiconductor devices such as thin-film transistors (TFTs) due to its low cost, non-toxicity, and superior electrical performance. However, the high oxygen vacancy (V_O) concentration leads to poor performance of SnO₂ thin films and devices. In this paper, with tetraethyl orthosilicate (TEOS) as the Si source, which can decompose to release heat and supply energy when annealing, Si doped SnO₂ (STO) films and inverted staggered STO TFTs were successfully fabricated by a solution method. An XPS analysis showed that Si doping can effectively inhibit the formation of V_O, thus reducing the carrier concentration and improving the quality of SnO₂ films. In addition, the heat released from TEOS can modestly lower the preparation temperature of STO films. By optimizing the annealing temperature and Si doping content, 350 °C annealed STO TFTs with 5 at.% Si exhibited the best device performance: I_off was as low as 10^-10 A, I_on/I_off reached a magnitude of 10⁴, and V_on was 1.51 V. Utilizing TEOS as an Si source has a certain reference significance for solution-processed metal oxide thin films in the future.

Keywords: oxygen vacancy; tetraethyl orthosilicate; thin-film transistors; tin oxide.

Grants and funding

This work was supported by National Natural Science Foundation of China (Grant No.22090024 and 62174057), Southwest Institute of Technology and Engineering Cooperation Fund (HDHDW5902020402), Key-Area Research and Development Program of Guangdong Province (No.2020B010183002), Special Fund for Science and Technology Innovation Strategy of Guangdong Province in 2021 (“Big Special Project+Task List”) Project(No.210908174533730), Guangdong Major Project of Basic and Applied Basic Research (No.2019B030302007), National Natural Science Foundation of China (Grant No.62074059) and Ji Hua Laboratory scientific research project (X190221TF191).