Amorphous IGZO TFTs with Low Electrical Hysteresis By Using Two-Photomask Process Academic Article uri icon

abstract

  • Amorphous oxide semiconductor (AOS)-based TFTs have been considered as potential channel materials for high-resolution TFT-LCDs and AMOLEDs [1-3]. However, the electrical characteristics of AOS TFTs frequently deteriorate with increasing operating cycle times because of the increased trap states present in the AOS semiconductor layer. In this work, we demonstrated the amorphous Indium-Gallium-Zinc-oxide (a-IGZO) TFT fabricated by using two-photomask process [4], which can effectively reduce the process complexity and manufacture cost. Experiment The TFT manufacture processes are as followed. A Mo film was deposited by DC sputtering on glass substrate as gate electrode. After patterning, the tri-layer structure of HfO2 /IGZO/ HfO2 film was deposited as gate insulator, channel and passivation layer respectively. The pattern of channel and passivation layer was defined by photolithography with back exposure. Finally, using DC sputtering deposited the MO films and patterned to form the source/drain electrode. Result and Discussion In this work, experimental results have shown that the 2-photomask fabricated a-IGZO TFT can exhibit superior performance with a subthreshold swing of 66 mV/dec., threshold voltage of -0.37V, field effect mobility of 10 cm2/VS, Ion/Ioff current ratio of ~107 and extremely low electrical hysteresis loop V=10mV was obtained. The reliability of a-IGZO TFTs also was measured and investigated, it reveals the great reliability because the passivation layer can effectively isolate the reaction between the back-channel and atmosphere. It is highly promising to be applied for the emerging transparent display backplane technologies. Reference [1] K. Nomura, H. Ohta, A. Takagi, T. Kamiya, M. Hirano, and H. Hosono, nature, vol. 432, no. 7016, pp. 488-492, 2004. [2] J. Yao, N. Xu, S. Deng, J. Chen, J. She, H.P. D. Shieh, P.T. Liu, and Y.P. Huang, IEEE Transactions on Electron Devices, vol. 58, no. 4, pp. 1121-1126, 2011. [3] P.Y. Kuo, C.M. Chang, I.H. Liu, and P.T. Liu, Scientific reports, vol. 9, no. 1, pp. 1-7, 2019. [4] Y. Kuo, Journal of The Electrochemical Society, vol. 138, no. 2, pp. 637, 1991. Figure 1

published proceedings

  • ECS Meeting Abstracts

author list (cited authors)

  • Li, Z., Chiang, T., Liu, P., & Kuo, Y.

citation count

  • 0

publication date

  • November 2020