Fluorinated Metal-Oxide Thin-Film Transistors for Circuit Implementation on a Flexible Substrate


The effects of fluorination on amorphous indium-gallium-zinc oxide thin-film transistors and circuits fabricated on a polyimide flexible substrate were studied. Attributed to more effective passivation of donor-defects for a given thermal budget, fluorination resulted in suppressed apparent short-channel effects and better uniformity of turn-on voltage with reduced negative shift after laser lift-off from a glass carrier substrate. As representative digital circuits, 2-4 decoders were fabricated and characterized to demonstrate the advantages of incorporating fluorination in the construction of circuit building blocks, leading to higher gain, wider noise margins, more tightly distributed transition voltage and larger output swing.

Date of Publication: December 31, 2021
Electronic ISSN: 2768-167X
Publisher: IEEE

Runxiao Shi

Department of Electronic and Computer Engineering, the Hong Kong University of Science and Technology, Hong Kong (HKUST). (e-mail: rshiab@connect.ust.hk)

Sisi Wang

Department of Electronic and Computer Engineering, the Hong Kong University of Science and Technology, Hong Kong (HKUST).

Zhihe Xia

Department of Electronic and Computer Engineering, the Hong Kong University of Science and Technology, Hong Kong (HKUST).

Lei Lu

Department of Electronic and Computer Engineering, the Hong Kong University of Science and Technology, Hong Kong (HKUST) and School of Electronic and Computer Engineering, Peking University, Shenzhen, China.

Man Wong

Department of Electronic and Computer Engineering, the Hong Kong University of Science and Technology, Hong Kong (HKUST).


1.K. Nomura, H. Ohta, A. Takagi, T. Kamiya, M. Hirano and H. Hosono, "Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors", Nature, vol. 432, no. 7016, pp. 488-492, Nov. 2004.

2.R. Martins et al., "Papertronics: Multigate paper transistor for multifunction applications", Appl. Mater. Today, vol. 12, pp. 402-414, Sep. 2018.

3.B. Kim et al., "Highly reliable depletion-mode a-IGZO TFT gate driver circuits for high-frequency display applications under light illumination", IEEE Electron Device Lett., vol. 33, no. 4, pp. 528-530, Feb. 2012.

4.K. Myny et al., "15.2 A flexible ISO14443-A compliant 7.5 mW 128b metal-oxide NFC barcode tag with direct clock division circuit from 13.56MHz carrier", IEEE ISSCC Dig. Tech. Papers, pp. 258-259, Feb. 2017.

5.M. Zulqarnain et al., "A flexible ECG patch compatible with NFC RF communication", NPJ Flexible Electron., vol. 4, no. 1, pp. 1-8, Dec. 2020.

6.S. Lee and A. Nathan, "Subthreshold Schottky-barrier thin-film transistors with ultralow power and high intrinsic gain", Science, vol. 354, pp. 302-304, Oct. 2016.

7.J. Biggs et al., "A natively flexible 32-bit arm microprocessor", Nature, vol. 595, no. 7868, pp. 532-536, Jul. 2021.

8.N. Papadopoulos, S. Steudel, A. J. Kronemeijer, M. Ameys and K. Myny, "Flexible 16nJ/c.s. 134S/s 6b MIM C-2C ADC using dual gate self-aligned unipolar metal-oxide TFTs", Proc. Cust. Integr. Circuits Conf., pp. 1-4, Apr. 2019.

9.T.-C. Huang et al., "Pseudo-CMOS: A design style for low-cost and robust flexible electronics", IEEE Trans. Electron Devices, vol. 58, no. 1, pp. 141-150, Jan. 2011.

10.A. Correia, R. Martins, E. Fortunato, P. Barquinha and J. Goes, "Design of a robust general-purpose low-offset comparator based on IGZO thin-film transistors", Proc. IEEE Int. Symp. Circuits Syst., pp. 261-264, Jul. 2015-July.

11.J. Yao et al., "Electrical and photosensitive characteristics of a-IGZO TFTs related to oxygen vacancy", IEEE Trans. Electron Devices, vol. 58, no. 4, pp. 1121-1126, Apr. 2011.

12.J. Kim et al., " A study on H 2 plasma treatment effect on a-IGZO thin film transistor ", J. Mater. Res., vol. 27, no. 17, pp. 2318-2325, Sep. 2012.

13.J. Li, L. Lu, Z. Feng, H. S. Kwok and M. Wong, "An oxidation-last annealing for enhancing the reliability of indium-gallium-zinc oxide thin-film transistors", Appl. Phys. Lett., vol. 110, no. 14, Apr. 2017.

14.M. D. H. Chowdhury, J. G. Um and J. Jang, "Remarkable changes in interface o vacancy and metal-oxide bonds in amorphous indium-gallium-zinc-oxide thin-film transistors by long time annealing at 250 °C", Appl. Phys. Lett., vol. 105, no. 23, Dec. 2014.

15.S. J. Kim, S. Yoon and H. J. Kim, "Review of solution-processed oxide thin-film transistors", Jpn. J. Appl. Phys., vol. 53, no. 2S, Jan. 2014.

16.W. Xu et al., "Low temperature solution-processed IGZO thin-film transistors", Appl. Surf. Sci., vol. 455, pp. 554-560, Oct. 2018.

17.W. A. MacDonald et al., "Latest advances in substrates for flexible electronics", J. Soc. Inf. Display, vol. 15, no. 12, pp. 1075-1083, 2007.

18.F. Liu et al., "Polyimide film with low thermal expansion and high transparency by self-enhancement of polyimide/SiC nanofibers net", RSC Adv., vol. 8, no. 34, pp. 19034-19040, 2018.

19.S. D. Kim et al., "Poly(amide-imide) materials for transparent and flexible displays", Sci. Adv., vol. 4, no. 10, Oct. 2018.

20.M. Hasegawa, T. Kaneki, M. Tsukui, N. Okubo and J. Ishii, "High-temperature polymers overcoming the trade-off between excellent thermoplasticity and low thermal expansion properties", Polymer, vol. 99, pp. 292-306, Sep. 2016.

21.W. J. Bae, M. K. Kovalev, F. Kalinina, M. Kim and C. Cho, "Towards colorless polyimide/silica hybrids for flexible substrates", Polymer, vol. 105, pp. 124-132, Nov. 2016.

22.K.-C. Ok et al., "The effects of buffer layers on the performance and stability of flexible InGaZnO thin film transistors on polyimide substrates", Appl. Phys. Lett., vol. 104, no. 6, Feb. 2014.

23.K. Remashan, D. K. Hwang, S. J. Park and J. H. Jang, "Impact of hydrogenation of ZnO TFTs by plasma-deposited silicon nitride gate dielectric", IEEE Trans. Electron Devices, vol. 55, no. 10, pp. 2736-2743, Oct. 2008.
24.K.-C. Ok, S. Oh, H.-J. Jeong, J. U. Bae and J.-S. Park, "Effect of alumina buffers on the stability of top-gate amorphous InGaZnO thin-film transistors on flexible substrates", IEEE Electron Device Lett., vol. 36, no. 9, pp. 917-919, Sep. 2015.

25.T. Kim, Y. Nam, J. Hur, S.-H.-K. Park and S. Jeon, " The influence of hydrogen on defects of In–Ga–Zn–O semiconductor thin-film transistors with atomic-layer deposition of Al 2 O 3 ", IEEE Electron Device Lett., vol. 37, no. 9, pp. 1131-1134, Sep. 2016.

26.P. J. Schubert and J. H. Nevin, "A polyimide-based capacitive humidity sensor", IEEE Trans. Electron Devices, vol. ED-32, no. 7, pp. 1220-1223, Jul. 1985.

27.H.-R. Kim, M. Furuta and S.-M. Yoon, "Highly robust flexible vertical-channel thin-film transistors using atomic-layer-deposited oxide channels and zeocoat spacers on ultrathin polyimide substrates", ACS Appl. Electron. Mater., vol. 1, no. 11, pp. 2363-2370, Nov. 2019.

28.K. C. Yung, D. W. Zeng and T. M. Yue, "XPS investigation of Upilex-S polyimide ablated by 355 nm Nd:YAG laser irradiation", Appl. Surf. Sci., vol. 173, no. 3, pp. 193-202, Mar. 2001.

29.L. Lu et al., "A comparative study on fluorination and oxidation of indium–gallium–zinc oxide thin-film transistors", IEEE Electron Device Lett., vol. 39, no. 2, pp. 196-199, Feb. 2018.

30.Z. Xia, L. Lu, J. Li, H.-S. Kwok and M. Wong, "P-15: The use of fluorination to enhance the performance and the reliability of elevated-metal metal-oxide thin-film transistors", SID Symp. Dig. Tech. Papers, vol. 49, no. 1, pp. 1235-1238, May 2018.

31.S. Wang et al., "Resilience of fluorinated indium-gallium-zinc oxide thin-film transistor against hydrogen-induced degradation", IEEE Electron Device Lett., vol. 41, no. 5, pp. 729-732, May 2020.

32.L. Lu, J. Li, H. S. Kwok and M. Wong, "High-performance and reliable elevated-metal metal-oxide thin-film transistor for high-resolution displays", IEDM Tech. Dig., pp. 32.2.1-32.2.4, Dec. 2017.

33.A. Valletta, P. Gaucci, L. Mariucci, G. Fortunato and F. Templier, "‘Hump’ characteristics and edge effects in polysilicon thin film transistors", J. Appl. Phys., vol. 104, no. 12, Dec. 2008.

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