Journal of Advanced Marine Engineering and Technology

The Korean Society of Marine Engineering (한국마린엔지니어링학회)
권호 표지

Characteristics of $(Pb_{1-x}La_x)(Zr_{0.5}Ti_{0.5})O_3$ thin films as a function of La content

$(Pb_{1-x}La_x)(Zr_{0.5}Ti_{0.5})O_3$ 박막의 La 치환량에 따른 특성

  • 정낙원 (한국해양대학교 전기전자공학부) ;
  • 이성환 (위덕대학교 에너지전기공학부) ;
  • 이동영 (위덕대학교 에너지전기공학부) ;
  • 김동훈 (경북대학교 전자전기컴퓨터학부)
  • Published : 2006.11.30
Download PDF
⟨ Previous Next ⟩

Abstract

The electrical characteristics associated with crystal structure changes as a function of La content for $(Pb_{1-x}La_x)(Zr_{0.5}Ti_{0.5})O_3$ thin films were investigated for applications in memory capacitors. Tetragonality of PLZT films decreased with increasing La content. Thin films with La $\geq$ 20 mol% were found to be cubic. Films with La $\geq$ 12 mol% exhibited broader dielectric peaks compared to those of bulk ceramics and behaved as relaxer ferroelectrics. Tetragonal PLZT film with 12 mol% La had a dielectric constant maximum of 1330 at room temperature and a charge storage density of ${\sim}18{\mu}C/cm^2$ at 5 V. Decrease in coercive field and remnant polarization with increase in La content were resulting from less dipolar response caused by the decreased crystal anisotropy. The leakage current densities $<10^{-8}A/cm^2$ up to 5 V bias voltage were observed for the films with La $\geq$ 14 mol%.

Keywords

References

  1. R. Mozzami,C. Hu and W. H. Shepherd., 'Electrical Characteristics of Ferroelectric PZT Thin Films for DRAM Applications', IEEE Trans. on Electron Devices ED-39, p.2044, 1992
  2. G. H Haetling and C. E. Land,'Hot-pressed (Pb,La)(Zr,Ti)O3 Ferroelectric Ceramics for Electrooptic Application', J. Am. Ceram. Soc., Vol.54, p.1, 1971
  3. T. Kawano, T. Sei, T. Tsuchiya, 'Preparation of Ferroelectric PLZT Thin Films by Sol-Gel Process and Dielectric Properties', Jpn. J. Appl. Phys. Vol. 30, p.2178, 1991 https://doi.org/10.1143/JJAP.30.2178
  4. S. B. Desu, 'Stresses in Ferroelectric Thin Films', Mat. Res. Soc. Symp. Proc., Vol.200, pp.199-204,1990
  5. D. Hennings and G. Rosenstein, 'X-ray Structure Investigation of Lanthanum Modified Lead Titanate with A-site and B-site Vacancies', Mat. Res. Bull., Vol.7, p.1505, 1972 https://doi.org/10.1016/0025-5408(72)90188-2
  6. W. Y. Gu, E. Furman, A. Bhalla and L. E. Cross,'Effects of Thermal Treatment on the electrical Properties in relaxor PLZT Ceramics', Ferroelectrics, Vol.89, pp.221-230, 1989 https://doi.org/10.1080/00150198908017900
  7. Y. Tanaka, M. Hirama and M. Ono, 'Dependence of Electro-Optic Properties of PLZT upon the Chemical Compositions', Ferroelectrics, Vol.94, pp.73-80, 1989 https://doi.org/10.1080/00150198908014235
  8. S. J. Kang, J. S. Ryoo, and Y. S. Yoon, 'The effects of La concentration on the properties of PLT thin films : from the perspective of DRAM application', Mat. Res. Soc. Symp. Proc., Vol.361, p.281, 1995