Journal of the Semiconductor & Display Technology (반도체디스플레이기술학회지)

The Korean Society Of Semiconductor & Display Technology (한국반도체디스플레이기술학회)
권호 표지

Current Variation in ZnO Thin-Film Transistor under Different Annealing Conditions

ZnO 박막트랜지스터의 어닐링 조건에 따른 전류 변화

  • Yoo, Dukyean (Department of Electrical and Computer Engineering, Ajou University) ;
  • Kim, Hyoungju (Department of Electrical and Computer Engineering, Ajou University) ;
  • Kim, Junyeong (Department of Electrical and Computer Engineering, Ajou University) ;
  • Jo, Jungyol (Department of Electrical and Computer Engineering, Ajou University)
  • 유덕연 (아주대학교 정보통신대학 전자공학과) ;
  • 김형주 (아주대학교 정보통신대학 전자공학과) ;
  • 김준영 (아주대학교 정보통신대학 전자공학과) ;
  • 조중열 (아주대학교 정보통신대학 전자공학과)
  • Received : 2014.02.25
  • Accepted : 2014.03.20
  • Published : 2014.03.31
Download PDF
⟨ Previous Next ⟩

Abstract

ZnO is a wide bandgap (3.3 eV) semiconductor with high mobility and good optical transparency. However, off-current characteristics of ZnO thin-film transistor (TFT) need improvements. In this work we studied the variation in ZnO TFT current under different annealing conditions. Annealing usually modifies gas adsorption at grain boundaries of ZnO. When oxygen is adsorbed, electron density decreases due to strong electronegativity of the oxygen, and TFT current decreases as a result. Our experiments showed that current increased after vacuum annealing and decreased after air annealing. We explain that the change of off-current is caused by the desorption and adsorption of oxygen at the grain boundaries.

Keywords

References

  1. Jo, J., Seo, O., Choi, H., and Lee, B., "Enhancement-mode ZnO thin-film transistor grown by metalorganic chemical vapor deposition," Applied Physics Express, Vol. 1, p. 041202, 2008. https://doi.org/10.1143/APEX.1.041202
  2. Adamopoulos, G., Bashir, A., Thomas, S., Gillin, W.P., Georgakopoulos, Shkunov, M., Baklar, M.A., Stingelin, N., Maher, R.C., and Cohen, L.F., "Spray-Deposited Li-Doped ZnO Transistors with Electron Mobility Exceeding $50cm^{2}$/Vs," Advanced Materials, Vol. 22, 4764 , 2010. https://doi.org/10.1002/adma.201001444
  3. Jo, J., Choi, H., Yun, J., Kim, H., Seo, O., and Lee, B.,"Improvement of on/off ratio in ZnO thin-film transistor by using growth interruptions during metalorganic chemical vapor deposition," Thin Solid Films, Vol. 517, 6337, 2009. https://doi.org/10.1016/j.tsf.2009.02.083
  4. Chu, M.C., Meena, J.S., Liu, P.T., Shieh, H.D., You, H.C., Tu, Y.W., Chang, F.C., and Ko, F.H., "Oxygen Plasma Functioning of Charge Carrier Density in Zinc Oxide Thin-Film Transistors," Applied Physics Express, Vol. 6, 076501, 2013. https://doi.org/10.7567/APEX.6.076501
  5. Nomura, K., Ohta, H., Takagi, A., Kamiya, T., Hirano, M., and Hosono, H., "Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors," Nature, Vol. 432, 488, 2004. https://doi.org/10.1038/nature03090
  6. Erhart, P., Klein, A., and Albe, K., "First-principles study on the structure and stability of oxygen related point defects in zinc oxide," Phys. Rev. B, Vol. 72, 085213, 2005. https://doi.org/10.1103/PhysRevB.72.085213