Structural defects and local chemistry across ferroelectric–electrode interfaces in epitaxial heterostructures
Structural defects and local chemistry across ferroelectric–electrode interfaces in epitaxial heterostructures
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DOI：
10.1007/s10853-009-3548-y
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发表时间：
2009-05
影响因子：
4.5
通讯作者：
M. Arredondo;Martin Saunders;A. Petraru;Hermann Kohlstedt;I. Vrejoiu;M. Alexe;Dietrich Hesse;Nigel D. Browning;Nigel D. Browning;Paul G Munroe;Valanoor Nagarajan
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文献类型：
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作者：
M. Arredondo;Martin Saunders;A. Petraru;Hermann Kohlstedt;I. Vrejoiu;M. Alexe;Dietrich Hesse;Nigel D. Browning;Nigel D. Browning;Paul G Munroe;Valanoor Nagarajan
本文对（001）取向外延铁电薄膜异质结构中底电极与铁电薄膜生长界面的化学性质进行了详细的研究。研究了在SrRuO3/SrTiO3上沉积的PbZr0.2Ti0.8O3、PbZr0.52Ti0.48O3和batio3三种不同的铁电体系，比较了晶格失配对沉积阳离子的挥发性的影响。基于透射电子显微镜的成像和光谱学的结合揭示了铁电薄膜组成、沉积过程和铁电电极界面上观察到的化学梯度之间的明显相关性。在PbZr0.2Ti0.8O3/SrRuO3/ srtio3薄膜中，Sr从电极向铁电膜的扩散占主导地位。相反，Pb在PbZr0.52Ti0.48O3/SrRuO3/ srtio3薄膜中普遍扩散。发现BaTiO3/SrRuO3/ srtio3异质结构具有原子尖锐的界面，没有任何相互扩散的特征。我们表明，在制造无缺陷铁电薄膜器件时，控制阳离子的挥发性与晶格失配一样重要。
We present a detailed investigation of the chemistry at the growth interface between the bottom electrode and ferroelectric film in (001)-oriented epitaxial ferroelectric thin-film heterostructures. Three different ferroelectric systems, namely PbZr0.2Ti0.8O3, PbZr0.52Ti0.48O3, and BaTiO3deposited on SrRuO3/SrTiO3, were investigated to compare and contrast the role of lattice mismatch versus the volatility of the deposited cation species. A combination of transmission electron microscopy-based imaging and spectroscopy reveals distinct correlations among the ferroelectric thin-film composition, the deposition process, and chemical gradients observed across the ferroelectric–electrode interface. Sr diffusion from the electrode into the ferroelectric film was found to be dominant in PbZr0.2Ti0.8O3/SrRuO3/SrTiO3thin films. Conversely, Pb diffusion was found to be prevalent in PbZr0.52Ti0.48O3/SrRuO3/SrTiO3thin films. The BaTiO3/SrRuO3/SrTiO3heterostructure was found to have atomically sharp interfaces with no signature of any interdiffusion. We show that controlling the volatility of the cation species is as crucial as lattice mismatch in the fabrication of defect-free ferroelectric thin-film devices.