Journal of the Institute of Electronics Engineers of Korea SD (대한전자공학회논문지SD)

The Institute of Electronics and Information Engineers (대한전자공학회)
권호 표지

A Study on the Switching and Retention Characteristics of PLT(5) Thin Films

PLT(5) 박막의 Switching 및 Retention 특성에 관한 연구

  • Choi Joon Young (Dept. of Electronics Engineering, Inha University) ;
  • Chang Dong Hoon (Dept. of Electronics Engineering, Inha University) ;
  • Kang Seong Jun (Dept. of Semiconductor Materials & Devices Yosu National University) ;
  • Yoon Yung Sup (Dept. of Electronics Engineering, Inha University)
  • Published : 2005.01.01
Download PDF
⟨ Previous Next ⟩

Abstract

We fabricate PLT(5) thin film on Pt/TiO/sub x/SiO₂/Si substrate by using sol-gel method and investigate leakage current, switching and retention properties. The leakage current density of PLT(5) thin film is 3.56×10/sup -7/A/㎠ at 4V. In the examination of switching properties, pulse voltage and load resistance were 2V～5V and 50Ω～3.3kΩ, respectively. Switching time has a tendency to decrease from 0.52㎲ to 0.14㎲ with the increase of pulse voltage, and also the time increases from 0.14㎲ to 13.7㎲ with the increase of load resistance. The activation energy obtained from the relation of applied pulse voltage and switching time is about 135kV/cm. The error of switched charge density between hysteresis loop and experiment of polarization switching is about 10%. Also, polarization in retention decreases as much as about 8% after l0/sup 5/s.

Sol-gel 법을 이용하여 Pt/TiO/sub x/SiO₂/Si 기판 위에 3.14×10/sup -4/㎠ 의 상부전극 면적을 갖는 PLT(5) 박막을 제작하여 스위칭 및 retention 특성에 대해 연구하였다. 4V 에서 3.56×10/sup -7/A/㎠의 누설전류밀도 값을 갖는 우수한 PLT(5) 박막에 펄스전압을 2V 에서 5V 까지 인가하였다. 펄스전압 증가에 따라 스위칭 시간은 0.52㎲ 에서부터 0.14㎲ 까지 감소하는 경향을 나타냈으며, 부하저항을 50Ω 에서 3.3Ω 으로 증가시킴에 따라 스위칭 시간이 0.14㎲에서 13.7㎲ 로 증가하는 것이 관찰되었다. 인가된 펄스 전압에 대한 스위칭 시간의 관계로부터 구한 활성화 에너지(Ea) 는 135kV/cm 이었다. PLT(5) 박막의 이력곡선과 분극 스위칭 실험으로부터 구한 switched charge density 사이의 오차는 약 10% 정도로 비교적 잘 일치하였으며, retention 특성은 105s 이후에도 약 8% 정도의 우수한 분극 감소 특성을 나타내었다.

Keywords

References

  1. C. P. de Araujo, J. F. Scott and G. W. Taylor, Ferroelectric Thin Films : Synthesis and Basic Properties, Gordon and Breach Publishers, Amsterdam, pp. 1-8, 1996
  2. F. Wang and G. H. Heartling, 'A PLZT Optical Phase Modulator and Its Applications', Proc. of 1992 IEEE International Symposium on Applications of Ferroelectrics, pp. 596-599, 1992 https://doi.org/10.1109/ISAF.1992.300735
  3. S. K Dey and J. J. Lee, 'Curie Paraelectric (Nonferroelectric) Perovskite PLT Thin Films with High Permittivity for ULSI DRAM's and Decoupling Capaditors', IEEE Trans. Electron Devices, vol.39, no.7, pp. 1607-1612, 1992 https://doi.org/10.1109/16.141225
  4. S. J Kang and Y. S. Yoon, 'Optical and Electrical Properties of Lanthanum-Modified Lead Titanate Thin Films with Various Lanthanum Concentrations', Jpn. J. Appl. Phys., vol. 36, no. 7, pp. 4459-4465, 1997 https://doi.org/10.1143/JJAP.36.4459
  5. 강성준, 정양희, 윤영섭, 'Pb/La 조성에 따른 (Pb,La)TiO3 박막의 특성변화', 전자공학회 논문지, vol.36D, no.1, pp.29-37, 1999
  6. I. S. Zheludev, Physics of Crystalline Dielectrics, Plenum, New York, pp. 474-490, 1971
  7. H. M. Duiker et al, 'Fatigue and Switching in Ferroelectric Memories: Theory and Experiment', J.Appl. Phys., vol.68, no.11, pp. 5783-5791, 1990 https://doi.org/10.1063/1.346948
  8. Byung Moo Song and Doh-Yeon Kim, Effect of Excess PbO The Densification of PLZT ceramics, J. Am. Ceram. Soc., vol. 72[5], pp. 833-836, 1989 https://doi.org/10.1111/j.1151-2916.1989.tb06226.x
  9. Y. S. Yoon et al. 'Switching properties of the PLT(10) Thin Film', Proc. of 2000 IEEE International Symposium on Applications of Ferroelectrics, pp. 941-944, 2000 https://doi.org/10.1109/ISAF.2000.942473
  10. A. K. Kulkarni, 'Thin Film Ferroelectric Materials and Devices', IRPS Tutorials, pp. 8.1-8.52, 1990
  11. M. E. Lines and A. M. Glass, Principles and Applications of Ferroelectrics and Related Materials, Oxford Univ. Press, Oxford, pp. 106, 1977
  12. P. C. Joshi and S. B. Krupanidhi, 'Switching, Fatigue and Retention in Ferroelectric Bi4Ti3O12 Thin Films', Appl. Phys. Lett., vol. 62, no. 16, pp. 1928-1930, 1993 https://doi.org/10.1063/1.109547
  13. J. J. Lee and S. B. Desu, 'Retention and Imprint Properties of Ferroelectric Thin Films', Phys. state. sol. vol. (a)151, pp. 171-182, 1995 https://doi.org/10.1002/pssa.2211510120
  14. Deborah J. Taylor, Ferroelectric Film Devices, Academic Press, pp. 28-30, 2000
  15. K. Koyama et al, 'A Stacked Capacitor with (BaxSr1-x)TiO3 for 256M DRAM', IEDM Tech. Digit., pp. 823-826, 1991