Fabrication of high-performance ZnO-based thin-film transistors by Mg/H co-doping at room temperature

• Published in: Journal of materials science. Materials in electronics 2022-02, Vol.33 (4), p.2080-2089
• Main Authors: Jiang, Zongjin, Yin, Dongbo, Zhu, Deliang, Xu, Wangying, Han, Shun, Fang, Ming, Liu, Wenjun, Cao, Peijiang, Liu, Xinke, Lu, Youming
• Format: Article
• Language: English
• Subjects: Argon; Carrier density; Characterization and Evaluation of Materials; Chemistry and Materials Science; Doping; Flexible components; Free energy; Heat of formation; Magnetron sputtering; Materials Science; Optical and Electronic Materials; Room temperature; Semiconductor devices; Silicon dioxide; Silicon substrates; Thin film transistors; Threshold voltage; Transistors; Zinc oxide
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-021-07412-1

We fabricated thin-film transistors (Mg 0.06 Zn 0.94 O:H-TFTs) in an argon and hydrogen (Ar + H 2 ) atmosphere by magnetron sputtering using Mg 0.06 Zn 0.94 O as the target material without heating the P ++ –Si/SiO 2 substrate. We studied the influence of Mg/H co-doping on film properties and device performance. Mg doping of the ZnO film increases the formation energy of oxygen vacancies and reduces that of interstitial hydrogen, whereas H doping acts as a shallow donor and passivates oxygen-related defects. On the one hand, the combined effect of the dopants modulated the carrier concentration of the film. On the other hand, the scattering of electrons by the interface trap states in the channel layer reduced, thereby improving the TFT performance. At H 2 /(Ar + H 2 ) = 0.39%, the overall performance of Mg 0.06 Zn 0.94 O:H-TFT is the best, with a saturation mobility of 8.11 cm 2 /Vs, an on/off-current ratio of 6.17 × 10 6 , a threshold voltage of 2.78 V and a subthreshold swing of 0.42 V/Dec, and the positive and negative bias stress stability values are 0.61 and − 1.02 V, respectively. Besides, all features are significantly improved compared with those of ZnO-TFT. The simple fabrication of high-performance Mg 0.06 Zn 0.94 O:H-TFTs under substrate at room temperature can promote ZnO-based TFT application in flexible electronics.