Low-frequency dielectric relaxation of BaTiO3 thin-film capacitors
Low-frequency dielectric relaxation of BaTiO3 thin-film capacitors
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DOI：
10.1063/1.124819
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发表时间：
1999-09
影响因子：
4
通讯作者：
Su-jae Lee;K. Kang;S. Han
中科院分区：
文献类型：
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作者：
Su-jae Lee;K. Kang;S. Han
采用溶胶-凝胶旋涂法在（111）Pt/Ti/SiO2/Si衬底上制备了具有钙钛矿结构的BaTiO 3铁电薄膜。为了研究钛酸钡薄膜中空间电荷的影响，我们测量了相对介电常数和薄膜的交流电导率作为频率，交流振荡幅度和温度的函数。介电常数和介电损耗分别为147和0.03在100 kHz。此外，BaTiO 3薄膜在居里温度以上和100 Hz以下的低频区域表现出明显的介电弛豫。这种低频介电弛豫归因于BaTiO_3薄膜中的氧空位和缺陷等电离空间电荷载流子以及界面极化。电离空间电荷载流子弛豫过程的热激活能为0.72 eV。
Ferroelectric BaTiO3 thin films with perovskite structure were grown by sol-gel spin-on processing onto (111)Pt/Ti/SiO2/Si substrates. In order to investigate the effects of space charge in BaTiO3 thin films, we measured the relative dielectric constant and the ac conductivity of the films as a function of frequency, ac oscillation amplitude, and temperature. Dielectric constant and dielectric loss were 147 and 0.03 at 100 kHz, respectively. Also, BaTiO3 thin films exhibited marked dielectric relaxation above the Curie temperature and in the low-frequency region below 100 Hz. This low-frequency dielectric relaxation is attributed to the ionized space-charge carriers such as oxygen vacancies and defects in BaTiO3 film and the interfacial polarization. The thermal activation energy for the relaxation process of the ionized space-charge carriers was 0.72 eV.