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Effects of the Introduction of UV Irradiation and Rapid Thermal Annealing Process to Sol-Gel Method Derived Ferroelectric Sr0.9Bi2.1Ta1.8Nb0.2O9 Thin Films on Crystallization and Dielectric/Electrical Properties

UV 노광과 RTA 공정의 도입이 Sol-Gel 법으로 제조한 강유전성 Sr0.9Bi2.1Ta1.8Nb0.2O9 박막의 결정성 및 유전/전기적 특성에 미치는 영향

  • 김영준 (고려대학교 재료공학과) ;
  • 강동균 (고려대학교 재료공학과) ;
  • 김병호 (고려대학교 재료공학과)
  • Published : 2004.01.01

Abstract

The ferroelectric SBT thin films as a material of capacitors for non-volatile FRAMs have some problems that its remanent polarization value is relatively low and the crystallization temperature is quite high abovc 80$0^{\circ}C$. Therefore, in this paper, SBTN solution with S $r_{0.9}$B $i_{2.1}$T $a_{1.8}$N $b_{0.2}$$O_{9}$ composition was synthesized by sol-gel method. Sr(O $C_2$ $H_{5}$)$_2$, Bi(TMHD)$_3$, Ta(O $C_2$ $H_{5}$)$_{5}$and Nb(O $C_2$ $H_{5}$)$_{5}$ were used as precursors, which were dissolved in 2-methoxyethanol. SBTN thin films with 200 nm thickness were deposited on Pt/Ti $O_2$/ $SiO_2$/Si substrates by spin-coating. UV-irradiation in a power of 200 W for 10 min and rapid thermal annealing in a 5-Torr-oxygen ambient at 76$0^{\circ}C$ for 60 sec were used to promote crystallization. The films were well crystallized and fine-grained after annealing at $650^{\circ}C$ in oxygen ambient. The electrical characteristics of 2Pr=11.94 $\mu$C/$\textrm{cm}^2$, Ps+/Pr+=0.54 at the applied voltage of 5 V were obtained for a 200-nm-thick SBTN films. This results show that 2Pr values of the UV irradiated and rapid thermal annealed SBTN thin films at the applied voltage of 5 V were about 57% higher than those of no additional processed SBTN thin films. thin films.lms.s.s.

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