Variations of ferroelectric properties with the addition of Yttrium acetate in the $Pb(Zr_{0.65}Ti_{0.35})O_3$ thin films prepared by Sol-Gel processing

Sol-Ge법에 의한 $Pb(Zr_{0.65}Ti_{0.35})O_3$박막의 Yttrium acetate 첨가에 따른 강유전 특성의 변화

  • 김준한 (연세대학교 전기공학과) ;
  • 이규선 (연세대학교 전기공학과) ;
  • 이두희 (연세대학교 전기공학과) ;
  • 박창엽 (연세대학교 전기공학과)
  • Published : 1995.05.01

Abstract

In this study, PZT solutions added impurities of Yttrium acetate were prepared by sol-gel processing and were deposited on Pt/ $SiO_{2}$/Si substrates at 5000 rpm for 20 sec. using spin-coating method. Coated films were annealed at 700-750.deg. C for 30 min. using conventional furnace method. Variations of the crystallographic structure and microstructure of PZT thin films with adding impurities were observed using XRD and SEM, and the electrical properties, such as relative permittivity, tan .delta., hysteresis curves and leakage currents, were measured. As the yttrium contents were increased, the remanent polarization and coercive field were decreased. Variations of remanent polarizations and coercive fields of pure and yttrium doped specimens according to polarization reversal cycles were observed using hysteresis measurement. PZT thin films added $Y^{3+}$ ions were completely crystallized at 750.deg. C. $Y^{3+}$ ions, as donor impurity, substituted Pb.sup 2+/ ions located at A-site of perovskite structure. By substitution of $Y^{3+}$ ions, leakage currents became less by decreasing the space charges. Degradation of remanent polarizations of Yttrium added specimens after fatigue was not observed and coercive fields increased more than those of pure PZT thin films.

Keywords