The Transactions of the Korean Institute of Electrical Engineers C (대한전기학회논문지:전기물성ㆍ응용부문C)

The Korean Institute of Electrical Engineers (대한전기학회)
권호 표지

A New Poly-Si TFT Employing Air-Cavities at the Edge of Gate Oxide

게이트 산화막 가장자리에 Air-cavity를 가지는 새로운 구조의 다결정 실리콘 박막 트랜지스터

  • 이민철 (서울대 공과대 전기공학부) ;
  • 정상훈 (서울대 공과대 전기공학부) ;
  • 송인혁 (서울대 공과대 전기공학부) ;
  • 한민구 (서울대 공과대 전기공학부)
  • Published : 2001.08.01
Download PDF
⟨ Previous Next ⟩

Abstract

We have proposed and fabricated a new poly-Si TFT employing air-cavities at the edges of gate oxide in order to reduce the vertical electric field induced near the drain due to low dielectric constant of air. Air-cavity has been successfully fabricated by employing the wet etching of gate oxide and APCVD (Atmospheric pressure chemical vapor deposition) oxide deposition. Our experimental results show that the leakage current of the proposed TFT is considerably reduced by the factor of 10 and threshold voltage shift under high gate bias is also reduced because the carrier injection into gate insulator over the drain depletion region is suppressed.

Keywords

References

  1. I-Wei Wu, Alan G Lewis, Tiao-Yuan Huang, Anne Chiang, 'Performance of Polysilicon TFT Digital Circuits Fabricated with Various Processing Techniques and Device Architectures', SID 90 Digest, pp307, 1990
  2. Y.Oana, 'Low Temperature Polycrystalline Silicon TFT Technology for Liquid Crystal Display', AMLCD 99, Digest of Tech., pp251, 1999
  3. Toshida Tsukasa, 'TFT/LCD; Liquid-Crystal Displays addressed by Thin-Film Transistors', Japanese Technology Reviews, v29, p.26, 1996
  4. J.G. Fossum, A.O. Conde, H. Shichijo and S.K. Banerjee, Anomalous leakage current in LPCVD polysilicon MOSFETs, IEEE Trans. Electron Devices, vol. ED-32, no. 9, p.1878, 1985
  5. Seki, O. Kogure and B. Tsujiyama, Leakage current characteristics of offset-gated structure polycrystalline silicon MOSFETs, IEEE Electron Device Lett., vol. EDL-8, p.434, 1987
  6. B.H. Min, C.M. Park, and M.K. Han, 'A Novel Offset Gated Polysilicon Thin Film Transistor without an Additional Offset Mask', IEEE Electron Device Lett., vol. 16, No. 5, p.161, 1995 https://doi.org/10.1109/55.382226
  7. K. Tanaka, K. Nakazawa, S.Suyama, and K. Kato, 'Characteristics of Field-Induced-Drain (FID) Poly-Si TFT's with High On/Off Current ratio', IEEE Trans. Electron Devices, vol. 39, no. 4, p.916, 1992 https://doi.org/10.1109/16.127483
  8. K. Nakazawa, K. Tanaka, S. Suyama, K. Kato, and S. Kohda, 'Lightly Doped Drain TFT Structure for Poly-Si LCDs', SID 90 Digest, pp311, 1990
  9. 유준석, 민병혁, 박철민, 한민구, 'Birds beak 효과를 이용한 T형 게이트 폴리실리콘 박막 트랜지스터', 전기학회논문지 제45권 2호, 1996. 7
  10. Micheal Hack, Alan G. Lewis, I-Wei Wu, 'Physical Model for Degradation Effects in Polysilicon Thin-Film Transistors', IEEE Trans. Electron Devices, Vol.40, No.5, p. 890, 1993 https://doi.org/10.1109/16.210195
  11. G.Fortunato, A.Pecora, G.Tallarida, L.Mariucci, C.Reita, and P.Migliorato, 'Hot Carrier Effects in n-Channel Polycrystalline Silicon Thin Film Transistors: A Correlation Between Off-current and Transconductance Variation', IEEE Trans. Electron Devices, Vol.41, No.3, p. 340, 1994 https://doi.org/10.1109/16.275218