Bias Stability of a-IGZO TFT and a new Shift-Register Design Suitable for a-IGZO TFT

Authors: Young Wook Lee, Sun-Jae Kim, Soo-Yeon Lee, Moon-Kyu Song, Woo-Geun Lee Min-Koo Han

Abstract:

We have fabricated a-IGZO TFT and investigated the stability under positive DC and AC bias stress. The threshold voltage of a-IGZO TFT shifts positively under those biases, and that reduces on-current. For this reason, conventional shift-register circuit employing TFTs which stressed by positive bias will be unstable, may do not work properly. We have designed a new 6-transistor shift-register, which has less transistors than prior circuits. The TFTs of the proposed shift-register are not suffering from positive DC or AC stress, mainly kept unbiased. Despite the compact design, the stable output signal was verified through the SPICE simulation even under RC delay of clock signal.

Keywords: Indium Gallium Zinc Oxide (IGZO), Thin FilmTransistor (TFT), shift-register

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1075609

References:

[1] H. Yubata et al., "High-mobility thin-film transistor with amorphous InGaZnO4 channel fabricated by room temperature rf-magnetron sputtering", Appl. Phys. Lett. 89, 112123 (2006).
[2] H. Hosono et al.,"Recent progress in transparent oxide semiconductors: Materials and device application", Thin Solid Films 515 (2007).
[3] J-H. Lee et al, "World's largest (15-inch) XGA AMLCD panel using IGZO oxide TFT, SID 08 Digest, PP.625 (2008)
[4] S.H. Moon et al, US20070177438
[5] Yong Ho Jang, US20060146978
[6] Abbas Jamshidi-Roudbari, Shahrukh Akbar Khan and Miltiadis K. Hatalis, "High-Frequency Half-Bit Shift Register With Amorphous-Oxide TFT", IEEE ELECTRON DEVICE LETTERS, VOL. 31, NO. 4, (2010)
[7] T. Osada, K. Akimoto, T. Sato, M. Ikeda, M. Tsubuku, J. Sakata, J. Koyama, T. Serikawa, and S. Yamazaki, "Development of driverintegrated panel using amorphous In-Ga-Zn-Oxide TFT," in Proc. SID Symp. Dig., vol. 40, pp. 184-187 (2009)
[8] Jae Kyeong Jeong, Hui Won Yang, Jong Han Jeong, Yeon-Gon Mo, and Hye Dong Kim, "Origin of threshold voltage instability in indium-gallium-zinc oxide thin film transistors", Appl. Phys. Lett. 93, 123508 (2008)
[9] Ken Hoshino, David Hong, Hai Q. Chiang, and John F. Wager, "Constant-Voltage-Bias Stress Testing of a-IGZO Thin-Film Transistors", IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 56, NO. 7 (2009)
[10] A. Suresh and J. F. Muth, "Bias stress stability of indium gallium zinc oxide channel based transparent thin film transistors", Appl. Phys. Lett. 92, 033502 (2008)
[11] In-Tak Cho, Jeong-Min Lee, Jong-Ho Lee and Hyuck-In Kwon, "Charge trapping and detrapping characteristics in amorphous InGaZnO TFTs under static and dynamic stresses", Semicond. Sci. Technol. 24 (2009)
[12] Sangwon Lee et al., "Electrical stress-induced instability of amorphous indium-gallium-zinc oxide thin-film transistors under bipolar ac stress", APPLIED PHYSICS LETTERS 95, 132101 (2009)
[13] Tze-Ching Fung, Katsumi Abe, Hideya Kumomi and Jerzy Kanicki, "DC/AC Electrical Instability of R.F. Sputter Amorphous In-Ga-Zn-O TFTs", SID 09 DIGEST (2009)