薄膜厚度对Y掺杂Ba_(0.6)Sr_(0.4)TiO_3薄膜结构及介电性能的影响  

Effect of Film Thickness on Structure and Dielectric Properties of Yttrium-Doped Ba_(0.6)Sr_(0.4)TiO_3 Films

作　　者：徐从玉[1] 廖家轩[1] 王滨[1] 张宝[1] 李嶷云 张高俊[1] 

机构地区：[1]电子科技大学,四川成都610054

出　　处：《稀有金属材料与工程》2013年第S1期90-92,共3页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51172034);中央高校基金(ZYGX2009X018);电子科技大学中青年学术带头人培养基金(Y02018023601053)

摘　　要：采用溶胶-凝胶法(Sol-gel)在Si/SiO2/Ti/Pt基片上制备了不同厚度(正比于薄膜层数)的钇(Y)掺杂Ba0.6Sr0.4TiO3(BST)薄膜,研究了膜厚度对薄膜结构和介电性能的影响。原子力显微镜(AFM)表明,Y掺杂BST薄膜可显著改善表面形貌,且强烈依赖于薄膜厚度。当薄膜厚度适中(即当层数为8)时,表面晶粒细小、致密、均匀,晶界分明。X射线衍射(XRD)表明,Y掺杂BST薄膜显示钙钛矿结构,主要沿(110)晶面生长。随着薄膜厚度的增加,BST(110)峰的衍射强度先增后减,表明薄膜的相结构与薄膜厚度直接相关。Y掺杂BST薄膜显示优异的综合介电性能,且随着膜厚的增加,电容或介电常数减小。8层薄膜的综合介电性能最优,零偏压时的电容为17.8pF(介电常数130)、介电损耗为0.0057,调谐率为32%,优值因子为56,可满足微波调谐器件的需要。同时,就有关机理进行了分析。Yttrium-doped Ba0.6Sr0.4TiO3 thin films with different thickness (related with layer number of BST films) were prepared by Sol-gel method. The influence of thickness on structure and dielectric properties of the films were studied. Atomic force microscope shows that Y-doped BST films can improve the surface morphologies obviously, which is strongly related to film thickness. When the thickness is appropriate (the layer number is 8), the grain is smaller, denser and more homogeneous; the grain boundary is clear. However, X-ray diffraction pattern presents that the Y-doped BST films reveal perovskite structure and grow mainly along (110) orientation. With the increase of thickness, the diffraction intensity of (110) peak first increases and then decreases, which indicates that phase structure is related to the film thickness. The Y-doped BST films show markedly improved dielectric properties related to film thickness. When the thickness increases, the capacitance or the dielectric constant decreases. The film with 8 layers shows the best dielectric properties. The capacitance is 17.8 pF (the dielectric constant is 130) and the dielectric loss (tanδ) is 0.0057 at zero bias. The tunability can reach 32% and the figure of merit is 56. The Y-doped BST thin films with above marked performance can satisfy the requirements of microwave tuning device. The related mechanism was also analyzed.

关 键 词：Ba0.6Sr0.4TiO3薄膜 钇掺杂 介电性能 薄膜厚度 

分 类 号：O484.1[理学—固体物理]