Thickness dependence of ferroelectricity in heteroepitaxial BaTiO3 thin film capacitors
Thickness dependence of ferroelectricity in heteroepitaxial BaTiO3 thin film capacitors
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DOI：
10.1143/jjap.38.5305
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发表时间：
1999-09-01
期刊：
影响因子：
--
通讯作者：
Kawakubo, T
中科院分区：
文献类型：
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作者：
Yanase, N;Abe, K;Kawakubo, T
采用射频磁控溅射两步沉积技术，在SrRuO3/SrTiO3衬底上制备了厚度从12 nm到79 nm不等的BaTiO3异质外延薄膜，并对薄膜的晶体学和铁电性能进行了评价。当厚度减小到12 nm时，在异质外延BaTiO3薄膜中仍明显观察到铁电滞后回线，这可能是通过优化制备工艺提高了铁电薄膜与电极界面的结晶度所致。在200℃时观察到的迟滞现象可以用晶格失配应变将居里温度从固有的130℃修正到远高于200℃来解释。讨论了人为提高居里温度与铁电性的有限厚度依赖性之间的可能关系。
Heteroepitaxial BaTiO3 films of various thicknesses ranging from 12 nm to 79 nm were prepared on SrRuO3/SrTiO3 substrates by radio-frequency magnetron sputtering employing a two-step deposition technique, and the crystallographic and ferroelectric properties of the heteroepitaxial films were evaluated. A ferroelectric hysteresis loop was clearly observed in the heteroepitaxial BaTiO3 films even when the thickness was reduced to 12 nm, probably due to improved crystallinity at the interface between the ferroelectric film and the electrodes through optimization of the preparation technique. The observation of hysteresis at the temperature of 200 degrees C was explained in terms of modification of the Curie temperature from the inherent 130 degrees C to far above 200 degrees C by lattice misfit strain. A possible relationship between the artificially raised Curie temperature and the limited thickness dependence of ferroelectricity was discussed.