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Analysis of An Anomalous Hump Phenomenon in Low-temperature Poly-Si Thin Film Transistors

저온 다결정 실리콘 박막 트랜지스터의 비정상적인 Hump 현상 분석

  • Kim, Yu-Mi (Department of Electronics Engineering, Chungnam National University) ;
  • Jeong, Kwang-Seok (Department of Electronics Engineering, Chungnam National University) ;
  • Yun, Ho-Jin (Department of Electronics Engineering, Chungnam National University) ;
  • Yang, Seung-Dong (Department of Electronics Engineering, Chungnam National University) ;
  • Lee, Sang-Youl (Department of Electronics Engineering, Chungnam National University) ;
  • Lee, Hi-Deok (Department of Electronics Engineering, Chungnam National University) ;
  • Lee, Ga-Won (Department of Electronics Engineering, Chungnam National University)
  • Received : 2011.08.30
  • Accepted : 2011.09.26
  • Published : 2011.11.01

Abstract

In this paper, we investigated an anomalous hump phenomenon under the positive bias stress in p-type LTPS TFTs. The devices with inferior electrical performance also show larger hump phenomenon. which can be explained by the sub-channel induced from trapped electrons under thinner gate oxide region. We can confirm that the devices with larger hump have larger interface trap density ($D_{it}$) and grain boundary trap density ($N_{trap}$) extracted by low-high frequency capacitance method and Levinson-Proano method, respectively. From the C-V with I-V transfer characteristics, the trapped electrons causing hump seem to be generated particularly from the S/D and gate overlapped region. Based on these analysis, the major cause of an anomalous hump phenomenon under the positive bias stress in p-type poly-Si TFTs is explained by the GIDL occurring in the S/D and gate overlapped region and the traps existing in the channel edge region where the gate oxide becomes thinner, which can be inferred by the fact that the magnitude of the hump is dependent on the average trap densities.

Acknowledgement

Supported by : 한국과학재단

References

  1. T. Serikawa, S. Shirai, A. Okamoto, and S. Suyama, IEEE Trans. Elec. Dev., 36, 1929 (1989). https://doi.org/10.1109/16.34272
  2. K. Chung, M. P. Hong, C. W. Kim, and I. Kang, IEDM Tech. Dig., 385 (2002).
  3. Y. C. Wu, T. C. Chang, P. T. Liu, C. S. Chen, C. H. Tu, H. W. Zan, Y. H. Tai, and C. Y. Chang, IEEE Trans. Elec. Dev., 52, 2343 (2005). https://doi.org/10.1109/TED.2005.856797
  4. M. W. Ma, C. Y. Chen, W. C. Wu, C. J. Su, K. H. Kao, T. S. Chao, and T. F. Lei, IEEE Trans. Elec. Dev., 55, 1153 (2008). https://doi.org/10.1109/TED.2008.919710
  5. J. G. Fossum, A. Oritz-Vonde, H. Shichijo, and S. K. Banerjee, IEEE Trans. Elec. Dev., 32, 1878 (1985). https://doi.org/10.1109/T-ED.1985.22212
  6. H. C Kim and Y. H. Roh, J. KIEEME, 21, 213 (2008).
  7. C. F. Huang, C. Y. Peng, Y. J. Yang, H. C. Sun, H. C. Chang, P. S. Kuo, H. L. Chang, C. Z. Liu, and C. W. Liu, IEEE Electron Device Lett., 29, 1332 (2008). https://doi.org/10.1109/LED.2008.2007306
  8. W. K. Park, J. H. Lee, and G. Lim, IEEE Electron Device Lett., 25, 532 (2004). https://doi.org/10.1109/LED.2004.832121
  9. C. T. Tsai, T. C. Chang, S. C. Chen, I. Lo, S. W. Tsao, M. C. Hung, J. J. Chang, C. Y. Wu, and C. Y. Huang, Appl. Phys. Lett., 96, 242105 (2010). https://doi.org/10.1063/1.3453870
  10. M. Mativenga, M. H. Choi, J. Jang, R. Mruthyunjaya, T. J. Tredwell, E. Mozdy, and C. K. Williams, IEEE Trans. Elec. Dev., 58, 2440 (2011). https://doi.org/10.1109/TED.2011.2155068
  11. H. R. Park, D. Kwon, and J. D. Cohen, J. Appl. Phys., 83, 8051 (1998). https://doi.org/10.1063/1.367898
  12. C. S. Lin, Y. C. Chen, T. C. Chang, H. W. Li, S. C. Chen, F. Y. Jian, Y. S. Chuang, T. C. Chen, Y. C. Chen, and Y. H. Tai, J. Electrochem. Soc., 157, H1003 (2010). https://doi.org/10.1149/1.3483759
  13. Sigurd Wagner and C. N. Berglund, Rev. Sci. Instrum., 43, 1775 (1972). https://doi.org/10.1063/1.1685562
  14. J. Levinson, F. R. Shepherd, P. J. Scanlon, W. D. Westwood, G. Este, and M. Rider, J. Appl. Phys., 53, 1193 (1982). https://doi.org/10.1063/1.330583
  15. R. E. Proano, R. S. Misage, D. G. Ast, IEEE Trans. Elec. Dev., 36, 1915 (1989). https://doi.org/10.1109/16.34270
  16. R. L. Weisfield and D. A. Anderson, Phil. Mag. B 44, 83 (1981). https://doi.org/10.1080/01418638108222369