Journal of the Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회논문지)

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
권호 표지
DOI QR코드

DOI QR Code

Improvement of Electrical Performance and Stability in ZnO Channel TFTs with Al Doped ZnO Layer

Al Doped ZnO층 적용을 통한 ZnO 박막 트랜지스터의 전기적 특성과 안정성 개선

  • 엄기윤 (충남대학교 차세대기판학과) ;
  • 정광석 (충남대학교 전자전파정보통신공학과) ;
  • 윤호진 (충남대학교 전자전파정보통신공학과) ;
  • 김유미 (충남대학교 전자전파정보통신공학과) ;
  • 양승동 (충남대학교 전자전파정보통신공학과) ;
  • 김진섭 (충남대학교 전자전파정보통신공학과) ;
  • 이가원 (충남대학교 전자전파정보통신공학과)
  • Received : 2015.03.20
  • Accepted : 2015.04.07
  • Published : 2015.05.01
Download PDF
⟨ Previous Next ⟩

Abstract

Recently, ZnO based oxide TFTs used in the flexible and transparent display devices are widely studied. To apply to OLED display switching devices, electrical performance and stability are important issues. In this study, to improve these electrical properties, we fabricated TFTs having Al doped Zinc Oxide (AZO) layer inserted between the gate insulator and ZnO layer. The AZO and ZnO layers are deposited by Atomic layer deposition (ALD) method. I-V transfer characteristics and stability of the suggested devices are investigated under the positive gate bias condition while the channel defects are also analyzed by the photoluminescence spectrum. The TFTs with AZO layer show lower threshold voltage ($V_{th}$) and superior sub-threshold slop. In the case of $V_{th}$ shift after positive gate bias stress, the stability is also better than that of ZnO channel TFTs. This improvement is thought to be caused by the reduced defect density in AZO/ZnO stack devices, which can be confirmed by the photoluminescence spectrum analysis results where the defect related deep level emission of AZO is lower than that of ZnO layer.

Keywords

References

  1. K. Nomura, H. Ohta, A, Takagi, T. Kamiya, M. Hirano, and H. Hosono, Nature, 432, 488 (2004). https://doi.org/10.1038/nature03090
  2. S. Masuda, K. Kitamura, Y. Okumura, S. Miyatake, H. Tabata, and T. Kawai, J. Appl. Phys., 93, 1624 (2003). https://doi.org/10.1063/1.1534627
  3. U. Ozgur, Y. I. Alivov, C. Liu, A. Teke, M. A. Reshchikov, S. Doğan, V. Avrutin, S. J. Cho, and H. Morkoc, J. Appl. Phys., 98, 041301 (2005). https://doi.org/10.1063/1.1992666
  4. Y. Ohya, T. Niwa, T. Ban, and Y. Takahashi, Jpn. J. Appl. Phys., 40, 297 (2001). https://doi.org/10.1143/JJAP.40.297
  5. R.B.M. Cross, and M. M. De Souza, Appl. Phys. Lett., 89, 263513 (2006). https://doi.org/10.1063/1.2425020
  6. P. T. Liu, Y. T. Chou, and L. F. Teng, Appl. Phys. Lett., 95, 233504 (2009). https://doi.org/10.1063/1.3272016
  7. A. Janotti and C. G. Van de Walle, Rep. Prog. Phys., 72, 126501 (2009). https://doi.org/10.1088/0034-4885/72/12/126501
  8. J. S. Park, W. J. Maeng, H. S. Kim, and J. S. Park, Thin Solid Films, 520, 1679 (2012). https://doi.org/10.1016/j.tsf.2011.07.018
  9. D. J. Lee, H. M. Kim, J. Y. Kwon, H. Choi, S. H. Kim, and K. B. Kim, Adv. Func. Mater., 21, 448 (2011). https://doi.org/10.1002/adfm.201001342
  10. J. G. Lu, Z. Z. Ye, Y. J. Zeng, L. P. Zhu, L. Wang, J. Yuan, B. H. Zhao, and Q. L. Liang, J. Appl. Phys., 100, 073714 (2006). https://doi.org/10.1063/1.2357638
  11. T. Minami, H. Nanto, and S. Takata, Jpn. J. Appl. Phys., 23, L280 (1984). https://doi.org/10.1143/JJAP.23.L280
  12. K. H. Tam, C. K. Cheung, Y. H. Leung, A. B. Djurisic, C. C. Ling, C. D. Beling, S. Fung, W. M. Kwok, W. K. Chan, D. L. Phillips, L. Ding, and W. K. Ge, J. Phys. Chem. B, 110, 20865 (2006). https://doi.org/10.1021/jp063239w
  13. C. H. Ahn, Y. Y. Kim, D. C. Kim, S. K. Mohanta, and H. K. Cho, J. Appl. Phys., 105, 013502 (2009). https://doi.org/10.1063/1.3054175
  14. S. W. Xue, X. T. Zu, W. G. Zheng, M. Y. Chen, and X. Xiang, Phys. B: Cond. Matt., 382, 201 (2006). https://doi.org/10.1016/j.physb.2006.02.032