| Summary: | 碩士 === 國立交通大學 === 材料科學與工程系 === 88 === Metal-organic decomposition method (MOD) was used to prepare SrBi2Ta2O9 thin films on Pt/Ti/SiO2/Si substrate. The Ta substitution in SBT thin films with Ti4+ ,V5+ and W6+ ions was studied. The possible role of dopants in microstructure and electric properties of SBT thin films was investigated.
Results showed that the substitution of V for Ta could improve electrical properties of SBT thin films, including higher remanent polarization and lower leakage current. This phenomenon is attributed to microstructure change of the thin films. In Ti-doped systems, the improvement in electric properties of SBT thin films was due to the compensation of charge balance. In the other hand, it was found that a reverse effect was observed for W-doped SBT thin films. Smaller Pr and large leakage current was detected. The observed poor electrical properties could be related to the formation of Bi-W oxide secondary phase.
In addition, another secondary phase, composed of Bi and Ti was commonly observed in this SBT-based system, irrespectively of dopants type. However, the formation temperature of this secondary phase was also influenced by the dopants. The use of doping elements and doping quantity should be considered in order to improve properties of SBT thin films.
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