Characterization of Ferroelectric SrBi2Ta2 O 9 Thin Films Prepared from Alkoxide Solutions

Abstract

SrBi2Ta2O9 thin films prepared by chemical liquid deposition using alkoxide precursor solutions, followed by annealing at various temperatures, were characterized with a focus on the correlation between composition, microstructure, and ferroelectric properties. P-E hysteresis loops of the films exhibited well‐defined shapes at temperatures above 700°C, and the leakage current decreased with increasing annealing temperature, except for a film annealed at 4750°C. The crystal growth proceeded and ferroelectric properties of the films improved with increasing annealing temperature, whereas a large leakage current was observed for the film annealed at 750°C. Quantitative X‐ray photoelectron specroscopic analysis and high‐resolution transmission electron microscopic observation indicated the presence of a substantial amount of metallic bismuth in all films, predominantly in microcrystallite regions and on film surfaces, including the inner surface of cavities. The atomic fraction of metallic bismuth increased upon slight argon etching; however, the total bismuth content was significantly reduced. The metallic bismuth was amorphous and detected as vibrating spherical particles measuring approximately 5 nm under electron irradiation. The discontinuity in morphology, such as cavities at the interface between large single‐crystal grains and microcrystallite regions, was most remarkable in the film annealed at 750°C. The condensation of metallic bismuth at the cavities is believed to increase the leakage current when the path formed by cavities penetrates through the film. © 1999 The Electrochemical Society. All rights reserved.

BaTiO3 based relaxor ferroelectric epitaxial thin-films for high-temperature operational capacitors

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Interface stability of electrode/Bi-containing relaxor ferroelectric oxide for high-temperature operational capacitor

“…The Pt, TaC, and TiC electrodes show the spectra corresponding to the defective BT-BMN at approximately 157 and 162 eV. 28,29) In particular, in the case of Pt, after annealing, the defective state was pronounced strongly. The RuO 2 and TiC electrodes showed less annealing dependence of the change in the shape of Bi 4f and Ba 3d 5=2 spectra than the Pt and TaC electrodes.…”

(Invited) Combinatorial Synthesis and Interface Analysis for Development of High Dielectric Constant Thin Films

“…The peaks at approximately 158 and 163 eV correspond to Bi in the BT-BMN. In the spectra of the Stack-BT-BMN, peaks corresponding to a defective BT-BMN bonding state are observed at ~156 and ~161 eV in the lower-energy region; this state is related to oxygen vacancies in the BT-BMN films (26,27). By contrast, in the spectrum of Uniform-BT-BMN, peaks associated with a Bi2O3 bonding state appeared at ~159 and ~165 eV in the higher-energy region.…”