Characterization of Ferroelectric <TEX>$SrBi_2Ta_2O_9$</TEX> Thin Films Deposited by RF Magnetron Sputtering With Various Annealing Temperatures

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J. Korean Ceram. Soc. > Volume 34(2); 1997 > Article

Journal of the Korean Ceramic Society 1997;34(2): 202.

RF magnetron sputtering으로 제조된 강 유전체 $SrBi_2Ta_2O_9$ 박막의 열처리 온도에 따른 특성 연구

박상식, 양철훈, 윤순길, 안준형¹, 김호기¹

충남대학교 공과대학 재료공학과
¹한국과학기술원 재료공학과

Characterization of Ferroelectric $SrBi_2Ta_2O_9$ Thin Films Deposited by RF Magnetron Sputtering With Various Annealing Temperatures

ABSTRACT

Bi-layered SrBi2Ta2O9(SBT) films were deposited on Pt/Ti/SiO2/Si sibstrates by rf magnetron sputt-ering at room temperature and then were annealed at 75$0^{circ}C$, 80$0^{circ}C$ and 85$0^{circ}C$ for 1 hour in oxygen at-mosphere. The film composition of SrBi2Ta2O9 was obtained after depositing at room temperature and annealing at 80$0^{circ}C$. Excess 20mole% Bi2O3 and 30 mole% SrCO3 were added to the target to compensate for the lack of Bi and Sr in SBT film. 200 nm thick SBT film exhibited and dense microstructure, adielectric constant of 210, and a dissipation factor of 0.05 at 1 MHz frequency. The films exhibited Curie temperature of 32$0^{circ}C$ and a dielectric constant of 314 at that temperature under 100 kHz frequency. The remanent polarization(2Pr) and the coercive field(2Ec) of the SBT films were 9.1 $mu$C/$textrm{cm}^2$ and 85 kV/cm at an applied voltage of 3V, resspectively and the SBT film showed a fatigue-free characteristics up to 1010 cy-cles under 5V bipolar pulse. The leakage current density of the SBT film was about 7$times$10-7A/$textrm{cm}^2$ at 150 kV/cm. Fatigue-free SBT films prepared by rf magnetron sputtering can be suitable for application to non-volatile memory device.

Key words: Bi-layered $SrBi_2Ta_2O_9$(SBT), Rf magnetron sputtering, Nonvolatile memory device