Thickness effect on the ferroelectric properties of SBT thin films fabricated by LSMCD process

LSMCD공정으로 제조한 SBT 박막의 두께에 따른 강유전 특성

  • 박주동 (홍익대학교 공과대학 금속·재료공학과) ;
  • 권용욱 (홍익대학교 공과대학 금속·재료공학과) ;
  • 연대중 (홍익대학교 공과대학 금속·재료공학과) ;
  • 오태성 (홍익대학교 공과대학 금속·재료공학과)
  • Published : 1999.08.01

Abstract

$SrBi_{22.4}Ta_2O_9$ (SBT) thin films of 70~150 nm thickness were prepared on platinized silicon substrates by Liquid Source Misted Chemical Deposition (LSMCD) process, and their microstructure, feroelectric and leakage current characteristics were investigated. By annealing at $800^{\circ}C$ for 1 hour in oxygen ambient, SBT films were fully crystallized to the Bi layered perovskite structure without preferred orientation. The grain size of the LSMCD- derived SBT films was about 100nm, and was not varied with the film thickness. $2P_r$ and $E_c$ of the SBT films increased with decreasing the film thickness, and the 70nm-thick SBT film exhibited $2P_r$ of 17.8 $\mu$C/$\textrm{cm}^2$ and $E_c$ of 74kV/cm at applied voltage of 5V. Within the film thickness range of 70~150nm, the relative dielectric permittivity of the LSMCD-derived SBT film decreased with decreasing the film thickness. Leakage current densities lower than $10^{-7}\textrm{A/cm}^2$ at 5V were observed in the SBT films thicker than 125nm.

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