A Study on Low Temperature Sequential Lateral Solidification(SLS) Poly-Si Thin Film Transistors(TFT′s) with Molybdenum Gate

Molybdenum 게이트를 적용한 저온 SLS 다결정 TFT′s 소자 제작과 특성분석에 관한 연구

  • 고영운 (삼성전자 DS총괄 AMLCD 사업부) ;
  • 박정호 (고려대학 공과학과 전기공학과) ;
  • 김동환 (고려대학 공과학과 재료공학부) ;
  • 박원규 (LGPhilips-LCD 연구소)
  • Published : 2003.06.01


In this paper, we present the fabrication and the characteristic analysis of sequential lateral solidification(SLS) poly-Si thin film transistors(TFT's) with molybdenum gate for active matrix liquid displays (AMLCD's) pixel controlling devices. The molybdenum gate is applied for the purpose of low temperature processing. The maximum processing temperature is 55$0^{\circ}C$ at the dopant thermal annealing step. The SLS processed poly-Si film which is reduced grain and grain boundary effect, is applied for the purpose of electrical characteristics improvements of poly-Si TFT's. The fabricated low temperature SLS poly-Si TFT's had a varying the channel length and width from 10${\mu}{\textrm}{m}$ to 2${\mu}{\textrm}{m}$. And to analyze these devices, extract electrical characteristic parameters (field effect mobility, threshold voltage, subthreshold slope, on off current etc) from current-voltage transfer characteristics curve. The extract electrical characteristic of fabricated low temperature SLS poly-Si TFT's showed the mobility of 100~400cm$^2$/Vs, the off current of about 100pA, and the on/off current ratio of about $10^7$. Also, we observed that the change of grain boundary according to varying channel length is dominant for the change of electrical characteristics more than the change of grain boundary according to varying channel width. Hereby, we comprehend well the characteristics of SLS processed poly-Si TFT's witch is recrystallized to channel length direction.


fabrication;low temperature;Sequential Lateral Solidification(SLS);poly-silicon;thin film transistor(TFT)


  1. S. D. S. Malhi, H. Shichijo, S. K. Banerjee, R. Sundaresan, M. Elahy, G. P. Pollack, W. F. Richardson, A. H. Shah, L. R. Hite, R. H. Womack, P. K. Chatterjee and H. Wailam, 'Characteristics and Three-Dimensional Integration of MOSFET's in Small-Grain LPCVD Polycrystalline Silicon,' IEEE Trans. Electron Devices ED-32, pp.258-281, 1985
  2. Crowder, M. A. Carey, P. G. Smith, P. M. Sposili, R. S. Cho, H. S. Im, J. S, 'Low-temperature single-crystal Si TFTs fabricated on Si films processed via sequential lateral solidification,' IEEE Electron Device Letters, vol. 19, Issue 8, pp.306-308, August 1998 https://doi.org/10.1109/55.704408
  3. R. S. Sposili and J. S. Im, 'Line-scan sequential lateral solidification of Si thin films', Applied Physics A., vol. 63, no. 3, pp. 273-276, September 1998 https://doi.org/10.1007/s003390050770
  4. Robert A. Street (Ed.), Technology and Applications of Amorphous Silicon, Springer, 2000
  5. S. M. Sze, Physics of Semiconductor Device, John Wiley & Sons, 1981
  6. James S. Im, M. A. Crowder, Robert S. Sposili, J. P. Leonard, H. J. Kim, J. H. Yoon, Vikas V. Gupta, H. Jin Song, and Hans S. Cho, 'Controlled super-lateral growth of Si films for microstructural manipulation and optimization,' MRS, vol. 166, pp. 613-617, 1998 https://doi.org/10.1002/(SICI)1521-396X(199804)166:2<603::AID-PSSA603>3.0.CO;2-0
  7. 이윤재, 박정호, 김동환, 박원규, 양명수, 'SLS 공정을 이용한 p-type poly-Si TFT 제작에 관한 연구', 대한전기학회 논문지, 제51권, 6호, pp. 229-234, 2002. 6.
  8. 이윤재, 박정호, '단결정 실리콘 TFT 제작을 위한 SLS 공정', 2000년도 대한전기학회 추계부문학술대회 논문집, pp. 461-463, 2000. 11
  9. Sang-Hoon Jung, Cheon-Hong Kim, Juhn-Suk Yoo and Min-Koo Han, 'Offset-Gated Poly-Si TFTs Using in-situ Fluorine Passivation and Excimer Laser Doping', J. of Korean Physical Society, vol. 37, no. 6, pp. 866-869, December 2000 https://doi.org/10.3938/jkps.37.866
  10. Kubo, N., Kusumoto, N., Inushima, T., Yamazaki, S, 'Characteristics of polycrystalline-Si thin film transistors fabricated by excimer laser annealing method', Electron Devices, IEEE Transactions on, vol. 41, Issue 10, pp. 1876 -1879, October 1994 https://doi.org/10.1109/16.324604
  11. W. C. Omara, Liquid Crystal Displays Manufacturing Science and Technology, Van Nostrand, 1993
  12. James S. Im and H. J. Kim, 'On the super lateral growth phenomenon observed in excimer laser-induced crystallization of thin Si films', Applied Physics Letters, vol. 64, Issue 17, pp. 2303-2305, April 25, 1994 https://doi.org/10.1063/1.111651
  13. N. Yamauchi and R. Reif, 'Polycrystalline silicon thin films processed with silicon ion implantation and subsequent solid-phase crystallization: Theory, experiments, and thin-film transistor applications', Journal of Applied Physics, vol. 75, no. 7, April 1, 1994 https://doi.org/10.1063/1.356131
  14. IEEE Electron Device Letters v.19 no.Issue8 Low-temperature singlecrystal Si TFTs fabricated on Si films processed via sequential lateral solidification Crowder,M.A.;Carey,P.G.;Smith,P.M.;Sposili,R.S.;Cho,H.S.;Im,J.S https://doi.org/10.1109/55.704408