DOI QR코드

DOI QR Code

Study on the Shift in the P-E Hysteresis Curve and the Fatigue Behavior of the PZT Capacitors Fabricated by Reactive Sputtering

반응성 스퍼터링법으로 형성시킨 PZT 커패시티의 P-E 이력곡선의 이동현상 및 피로 특성 연구

  • 김현호 (한국과학기술원 신소재공학과) ;
  • 이원종 (한국과학기술원 신소재공학과)
  • Published : 2005.11.01

Abstract

[ $PZT(Pb(Zr,Ti)O_3)$ ] thin films were deposited by multi-target reactive sputtering method on $RuO_2$ substrates. Pure perovskite phase PZT films could be obtained by introducing Ti-oxide seed layer on the $RuO_2$ substrates prior to PZT film deposition. The PZT films deposited on the $RuO_2$ substrates showed highly voltage-shifted hysteresis loop compared with the films deposited on the Pt substrates. The surface of $RuO_2$ substrate was found to be reduced to metallic Ru in vacuum at elevated temperature, which caused the formation of oxygen vacancies at the initial stage of PZT film deposition and gave rise to the voltage shift in the P-E hysteresis loop of the PZT capacitor. The fatigue characteristics of the PZT capacitors under unipolar wane electric field were different from those under bipolar wane. The fatigue test under unipolar wane showed the increase of polarization. It was thought that the ferroelectric domains which had been pinned by charged defects such as oxygen vacancies and the charged defects were reduced in number by combining with the electrons injected from the electrode under unipolar wave, resulting in the relaxation of the ferroelectric domains and the increase of polarization.

Keywords

References

  1. G. J. Norga, S. Jin, L. Fe, D. J Wouters, H. Bender, and H. E. Maes, 'Growth of (111)-oriented $Pb(Zr,Ti)O_3$ layers on nanocrystalline $RuO_2$ electrodes using the sol-gel technique', Journal of Materials Research, Vol. 16, No.3, p. 828, 2001
  2. T. Nakamura, Y. Nakao, A. Kamisawa, and H. Takasu, 'Preparation of $Pb(Zr,Ti)O_3$ thin films on Ir and $IrO_2$ electrodes', Jpn. J Appl. Phys., Vol. 33, No. 9B, p. 5207, 1994
  3. G. Asano, H. Morioka, H. Funakubo, T. Shibutami, and N. Oshima, 'Fatigue-free $RuO_2/Pb(Zr,Ti)O_3/RuO_2$ capacitor prepared by metalorganic chemical vapor deposition at $395^{\circ}C$', Appl. Phys. Lett, Vol. 83, No. 26, p. 5505, 2003
  4. Y. Masuda and T. Nozaka, 'The influence of various upper electrodes on fatigue properties of perovskite $Pb(Zr,Ti)O_3$ thin films', Jpn. J Appl. Phys., Vol. 42, No. 9B, p. 5941, 2003
  5. H. N. AI-Shareef, K. R. Bellur, O. Auciello, and A I. Kingon, 'Effects of electrodes on the phase evolution and microstructure of $Pb(Zr_{0.53}Ti_{0.47})O_3$ films', Ferroelectrics, Vol. 152, p. 85, 1994
  6. H. Fukakubo, T. Hioki, M. Otsu, K. Shinozaki, and N. Mizutani, 'Film thickness dependence of dielectric property and crystal structure of $PbTiO_3$ film prepared on Pt/$SiO_2$/Si substrate by metal organic chemical vapor deposition', Jpn. J. Appl. Phys., Vol. 32, No. 9B, p. 4175, 1993
  7. H. Hase, T. Sakuma, Y. Miyasaka, K. Hirata, and N. Hosokawa, 'Preparation of $Pb(Zr,Ti)O_3$ thin films by multi-target sputtering', Jpn. J. Appl. Phys., Vol. 32, No. 9B, p. 4061, 1993
  8. S. O. Chung, J. W. Kim, G. H. Kim, C. O. Park, and W. J. Lee, 'Formation of a lead zirconate titanate (PZT)/Pt interfacial layer and structural changes in the Pt/Ti/$SiO_2$/Si substrate during the deposition of PZT thin film by electron cyclotron resonance plasma-enhanced chemical vapor deposition', Jpn. J. Appl. Phys., Vol. 36, No. 7A, p. 4386, 1997
  9. C. V. R. Vasant Kumar, R. Pascual, and M. Sayer, 'Crystallization of sputtered lead zirconate titanate films by rapid thermal processing', J. Appl. Phys., Vol. 71, No. 2, p. 864, 1992 https://doi.org/10.1063/1.351163
  10. J. J. Lee and S. B. Desu, 'Electrode contacts on ferroelectric thin films and their influence on fatigue properties', Ferroelectrics, Vol. 20, p. 27, 1995