Evolution of Ferroelectric Structure in SrBi2Ta2O9 Thin Films Prepared Using Triple Alkoxides on Pt-Passivated Si

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Abstract
Crystallization of triple-alkoxy-derived SrBi2Ta2O9 (SBT) thin films was initiated at temperatures below 500°C. For the 500°C-annealed thin films, the vibration modes of the oxygen sublattice of the SBT perovskite crystal were confirmed by Fourier-transform infrared spectroscopy (FT-IR) analysis. Calcination at 250°C in a mixture of water vapor and oxygen flow followed by rapid thermal annealing in the temperature range of 500–650°C affected the crystallinity and crystallographic orientation of SBT thin films. For these films, the strong infrared bands mainly corresponded to the dominant frequencies related to the optical polarization parallel to the c-axis. Simultaneously, grains grew and the surface topography changed significantly. The improvement of the crystallinity of the SBT perovskite phase and the increase in the grain size were responsible for the ferroelectric hysteresis properties in triple-alkoxy-derived SBT thin films annealed in the temperature range of 600–650°C