摘要
通过在溶胶前驱液中添加聚乙烯吡咯烷酮和在底电极Pt上形成界面仔晶层,对溶胶-凝胶(Sol-Gel)法进行了改进,并以此在Pt/Ti/SiO2/Si上制备了钇(Y)掺杂和非掺杂的Ba0.6Sr0.4TiO3(BST)薄膜,研究了薄膜的表面结构和介电调谐性能.X射线光电子能谱表明,BST薄膜表面元素都以两种或三种化学态出现,一种对应钙钛矿结构,其余的对应非钙钛矿结构.和非掺杂相比,除了Ti2p外,Y掺杂对Ba3d、Sr3d和O1s具有明显的影响,Ba、Sr和O原子在非钙钛矿结构中的含量分别由41%、33%和51%减少到26%、29%和40%.扫描电镜和原子力显微镜表明,Y掺杂BST薄膜光滑致密、无裂纹和无缩孔.40V偏压和100kHz频率下的电压-电容曲线表明,Y掺杂提高了薄膜的介电调谐性能,调谐率大于43%、损耗0.0216及优化因子20.对Y掺杂改性机理也进行了讨论.
Normal Sol-Gel method was improved by adding polyvinyl pyrrolidone to sol and forming seed layer on Pt electrode. Undoped and Yttrium （Y）-doped Ba0.6 Sr0.4TiO3 （BST） films were prepared on Pt/Ti/SiO2/Si by the improved Sol-Gel method. The surface structures and dielectric tunable properties of the as-prepared BST films were investigated. X-ray photoelectron spectrum （XPS） shows that Ba3d, Sr3d,Ti2p or Ols on the surfaces of BST films displays two or three chemical states, and these chemical states correspond to perovskited structure and non-perovskited structure. Y doping has significant effect on the chemical states of Ba3d, Sr3d and Ols except those of Ti2p, and makes the contents of Ba, Sr and O atoms in non-perovskited structure decrease from 41% to 26%, from 33% to 29% and from 51% to 40%, respectively, thus results in large decrease of non-perovskited structure. Meanwhile, scanning electron microscope （SEM） and atomic force microscope （AFM） demonstrate that Y-doped BST films show prominent improve- ment in morphologies with smooth and compact surface with no crack or shrinkage cavity. Such morphologies visibly decrease the adsorption of gases and hydrocarbon contaminations and their diffusion passes, which is the probable reason for non-perovskited structure to be formed. Also, voltage-capacitance curves obtained at 40V and 100kHz illustrate that Y-doped BST films exhibit improved dielectric tunable properties with tunability of more than 43 %, dielectric loss of 0.0216 and merit factor value of 20. Additionally, the improved mechanism of Y doping is discussed.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第2期387-391,共5页
Journal of Inorganic Materials
基金
电子科技大学中青年学术带头人培养计划(Y02018023601053)
博士点基金(20060614021)
四川省应用基础研究(2008JY0057)
