铈镁交替掺杂Ba_(0.6)Sr_(0.4)TiO_3薄膜高调谐性能  

High tunable dielectric properties of Ce and Mg alternately doped Ba_(0.6)Sr_(0.4)TiO_3 films

作　　者：胡一明[1] 廖家轩[1] 杨函于 王思哲[1] 吴孟强[1] 徐自强[1] 冯婷婷[1] 巩峰[1] 

机构地区：[1]电子科技大学能源科学与工程学院,成都611731

出　　处：《物理学报》2016年第14期261-267,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51172034;61101030);四川省科技计划(批准号:2015GZ0047;2015GZ0130)资助的课题~~

摘　　要：根据Ce掺杂、Mg掺杂以及Y和Mn交替掺杂可分别使Ba_(0.6)Sr_(0.4)TiO_3(BST)薄膜的介电调谐率、介电损耗和综合介电性能提高、降低和提高的特点,采用改进的溶胶-凝胶(sol-gel)法制备了6层Ce和Mg交替掺杂BST薄膜,并研究其结构及介电性能.Ⅹ射线衍射表明,该薄膜为立方钙钛矿结构、主要沿(110)晶面生长、晶化明显增强.扫描电子显微镜表明,薄膜表面形貌极大改善,首层薄膜与基体良好匹配,Ce掺杂层为首层的交替掺杂薄膜表面更均匀致密、晶粒更细小、晶化略微减弱.Ⅹ射线光电子能谱表明,薄膜表面非钙钛矿结构显著减少.薄膜显示高调谐率和高优质因子.Mg掺杂层为首层的交替掺杂薄膜在高频范围的综合介电性能更稳定.Ce掺杂层为首层的交替掺杂薄膜在低频范围的介电强度更高,综合性能更突出,在100 kHz下,10,20和40 V偏压对应的调谐率分别为47.4%,63.6%和71.8%,对应的优质因子分别为27.1,77.5和86.5,可满足微波调谐应用.同时,就有关机理进行了分析.For barium strontium titanate（Ba（0.6）Sr（0.4）TiO3, BST） films used in tunable microwave devices, they must have excellent structural characteristics and outstanding combination of dielectric properties i.e., a low loss tangent over the range of operating direct current（DC） bias voltages, a moderate dielectric constant for impedance matching purpose,a large variation in the dielectric constant with applied dc bias（high tunability, in particular high tunability at low applied dc bias）, etc. To achieve such a high objective, the following two great improvements are carried out. A normal sol-gel method is modified to prepare multilayer BST films layer by layer. Each multilayer BST film is composed of six layers, where each layer is preheated at 600？C, thus the layers from the first layer to the sixth layer are successively preheated once to six times. Thus each BST film is smooth and dense, and contains almost no organic residues. On the other hand, as a new doped mode, Ce/Mn alternate doping is performed. For every six layer-BST films, when the odd number layers are doped with Ce, then the even number layers are doped with Mg, vice versa. The above two improvements result from the fact that Ce doping, Mg doping and Y and Mn alternate doping could make BST thin films significantly improve the dielectric tunability, reduce the dielectric loss, and improve the combination of dielectric properties, respectively. According to the above two improvements, 1 mol% Ce and 3 mol% Mg alternately doped BST thin films are prepared on Pt/Ti/SiO2/Si wafers（substrates）. The prepared BST films are denoted by the doped element as follows： Ce/Mg/Ce/Mg/Ce/Mg with Ce doped BST layer is referred to as the first layer（for short Ce/Mg） and Mg/Ce/Mg/Ce/Mg/Ce with Mg doped BST layer as the first layer（Mg/Ce）, and the structure and dielectric properties of the films are studied. X-ray diffraction results show that two films present cubic perovskite structures, mainly grow along（110） crystal face, and show

关 键 词：铈镁交替掺杂 钛酸锶钡薄膜 高调谐 介电性能 

分 类 号：O484.4[理学—固体物理]