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

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

Switching Behaviour of the Ferroelectric Thin Film and Device Characteristics of MFSFET with Fatigue

피로현상을 고려한 강유전박막의 Switching 과 MFSFET 소자의 특성

  • Lee, Kook-Pyo (Dept. of Electronic Materials & Device Engineering, Inha Univ) ;
  • Kang, Seong-Jun (Dept. of Semiconductor and Applied Physics, Yosu National Univ.) ;
  • Yoon, Yung-Sup (Dept. of Electronic Materials & Device Engineering, Inha Univ)
  • 이국표 (仁荷大學校 電子材料工學科) ;
  • 강성준 (麗水大學校 半導體,慶用物理學科) ;
  • 윤영섭 (仁荷大學校 電子材料工學科)
  • Published : 2000.06.01
Download PDF
⟨ Previous Next ⟩

Abstract

Switching behaviour of the ferroelectric thin film and device characteristics of the MFSFET(Metal-Ferroelectric-Semiconductor FET) are simulated with taking into account the accumulation of oxygen vacancies near interface between the ferroelectric thin film and the bottom electrode caused by the progress of fatigue. In our switching model, relative switched charge is 0.74 nC before fatigue, but after the progress of fatigue it reduces to 0.15 nC with the generation of oxygen vacancies. It indicates that the generation of oxygen vacancies strongly suppresses polarization reversal. $C-V_G\;and\;I_D-V_G$ curves in our MFSFET device model exhibit the memory window of 2 V and show the accumulation, the depletion and the inversion regions in capacitance characteristic clearly. The difference of saturation drain current of the device before fatigue in shown by the dual threshold voltages in $I_D-V_G$ curve as 6nA/$cm^2$ and decreases as much as 50% after fatigue. Decrease of the difference of saturation drain currents by fatigue implies that the accumulation of oxygen vacancies with the fatigue should be avoided in the device application. Our simulation model is expected to play an important role in estimation of the behavior of MFSFET device with various ferroelectric thin films.

피로현상의 진행에 따라 발생하는 하부전극 주위의 산소공공 축적현상을 적용하여 강유전체 박막의 switching 특성과 MFSFET 소자특성을 시뮬레이션하였다. Switching 모델에서 relative switched charge는 피로현상 전에 0.74 nC 이였으나, 피로가 진행되어 50${\AA}$의 산소공공층이 생성된 후에는 불과 0.15nC 로서 산소공공층이 분극반전을 강력하게 억제함을 알았다. MFSFET 소자의 모델에서 C-V_G와 I_D-V_G 곡선은 2 V 의 memory window를 나타내었고, 캐패시턴스 특성에서 축적과 공핍 및 반전 영역은 확실하게 표현되었다. 그리고, $I_D-V_D$ 곡선에서 두 부분의 문턱전압에 의해 나타난 포화드레인 전류차이는 6mA/$cm^2$이었다. 그러나, 50${\AA}$의 산소공공층이 축적된 후, $I_D-V_D$ 곡선에서 포화 드레인 전류차이는 피로현상이 없는 경우에 비해 약 50% 감소하여 산소공공층이 소자 적용에 난제임을 확인하였다. 본 모델은 강유전체 박막의 다양한 특성과 임의의 강유전체 박막을 사용한 MFSFET 소자의 동작을 예측하는데 중요한 역할을 할 것으로 판단된다.

Keywords

References

  1. T. Sumi, 'Ferroelectric Nonvolatile Memory Technology and its Applications', International Conference on Solid State Devices and Materials, pp. 518-520, 1995
  2. S. Sinharoy, H. Buhay, D. R. Lampe and M. H. Francombe, 'Integration of Ferroelectric Thin Films into Nonvolatile Mermoies', J. Vac. Sci. Technol. A, vol. 10, pp. 1554-1560, 1992 https://doi.org/10.1116/1.578044
  3. I. K. Yoo and S. B. Desu, 'Fatigue Parameters of Lead Zirconate Titanate Thin Films', Mat. Res. Soc. Symp. Proc., vol. 243, pp.323-328, 1992
  4. J. J. Lee, T. M. Bhattacharya and S. B. Desu, 'Electrode Contacts on PZT Thin Films and Their Influence on Fatigue Properties', Mat. Res. Soc. Symp. Proc., vol. 361, pp. 241-247, 1995
  5. J. D. Jackson, Classical Electrodynamics, third edition, John Wiley & Sons, New York, Chapter 1, 1998
  6. F. K. Chai, J. R. Brews, R. D. Schrimpf and D. P. Bimie III, 'Relating Local Electric Field in a Ferroelectric Capacitor to Externally Measureable Voltages', Proceedings of the 9th Int. Symp. on Applications of Ferroelectrics, pp.83-86, 1994 https://doi.org/10.1109/ISAF.1994.522303
  7. J. A. Gonzalo, Effective Field Approach to Phase Transitions and Some Applications to Ferroelectrics, World Scientific Lecture Notes in Physics, vol. 25, World Scientific, New Jersey, 1991
  8. S. M. Sze, Physics cf Semiconductor Devices, second edition, John Wiley & Sons, New York, Chapter 8, 1981
  9. R. R. Pierret, Field Effect Devices, second edition, Addison-Wesley Publishing Company, Inc., USA, Chapter 2-3, 1990
  10. D. K. Schroder, Advanced MOS Devices, Addison-Wesley Publishing Company, Inc., USA, Chapter 1, 1987
  11. E. S. Yang, Microelectronic Devices, McGraw-Hill, Inc., USA, Chapter 9, 1988
  12. S. L. Miller and McWhorter, 'Physics of the Ferroelectric Nonvolatile Memory Field Effect Transistor', J. Appl. Phys, vol. 72 (12), pp. 5999-6012, 1992 https://doi.org/10.1063/1.351910
  13. P. C. Joshi and S. B. Krupanidhi, 'Switching, Fatigue, and Retention in Ferroelectric $Bi4Ti_3O_{12}$ Thin Films', Appl. Phys. Lett., vol. 62, pp. 1928~ 1930, 1993 https://doi.org/10.1063/1.109547
  14. H. M. Duiker, P. D. Beale, J. F. Scott, C. A. paz de Araujo, B. M. Melnick, J. D. Cuchiaro and L. D. McMillan, 'Fatigue and Switching in Ferroelectric Memories : Theory and Experiment', J. Appl. Phys., vol. 68, pp. 5783-5791, 1990
  15. Y. Fujimori, N. Izumi, T. Nakamura and A. Kamisawa, '$Sr_2(Ta,Nb)_2O_7$ Ferrolelectric Thin Film for Ferroelectric Memory FET', Integrated Ferroelectrics, vol. 21, Num. 1-4, pp. 73-82, 1998
  16. M. H. Lim, T. S. Kalkur and Y. T. Kim, 'Strontium Bismuth Tantalate Based Ferroelectric Gate Field Effect Transistor with yttrium Oxide as the Buffer Layer', Mat. Res. Soc. Symp. Proc., vol. 493, pp. 465-470, 1997