High-tunability and low-leakage current of the polycrystalline compositionally graded (Ba,Sr)TiO3 thin films derived by a sol–gel process
High-tunability and low-leakage current of the polycrystalline compositionally graded (Ba,Sr)TiO3 thin films derived by a sol–gel process
复制标题
DOI：
10.1016/j.matchemphys.2007.10.023
复制
发表时间：
2008-04
影响因子：
4.6
通讯作者：
Jun Wang;Tianjin Zhang;J. Xiang;Baishun Zhang
中科院分区：
文献类型：
--
作者：
Jun Wang;Tianjin Zhang;J. Xiang;Baishun Zhang
使用溶胶-凝胶技术在 Si 和 Pt/Ti/SiO2/Si 基底上沉积 x 从 0 增加到 0.4 的上下成分梯度 Ba1−xSrxTiO3(BST) 薄膜。通过 X 射线衍射 (XRD)、拉曼光谱、扫描电子显微镜 (SEM) 和原子力显微镜 (AFM) 对分级 BST 薄膜的微观结构进行了表征。降级的 BST 薄膜比升级的薄膜具有更大的介电常数和更低的介电损耗。在室温下施加250kVcm−1的电场和1MHz的测量频率时，向上和向下分级的BST薄膜的可调性分别为42.3%和38.9%。两种分级膜均具有低漏电流密度。同时，在低于 100kVcm−1 的外加电场下，降级薄膜的漏电流密度比升级 BST 薄膜低两个数量级。这可能是由于降级BST薄膜中的BaTiO3层不仅充当底层，而且还充当优良的籽晶层以改善薄膜的电性能。
Both up and down compositionally graded Ba1−xSrxTiO3(BST) thin films with increasing x from 0 to 0.4 were deposited on Si and Pt/Ti/SiO2/Si substrates using sol–gel technique. The microstructure of the graded BST films were characterized by X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The down graded BST film had a larger dielectric constant and lower dielectric loss than the up graded film. The tunability of the up and down graded BST films was 42.3 and 38.9%, respectively, at an applied field of 250kVcm−1and measurement frequency of 1MHz at room temperature. Both of the graded films had low-leakage current density. While, the leakage current density of down graded film lower two orders than the up graded BST film at the applied electric field below 100kVcm−1. This may be due to the BaTiO3layer in the down graded BST film not only serves as a bottom layer but also as an excellent seeding layer to improve the electric properties of the film.