Mg掺杂对Ba_(0.5)Sr_(0.5)TiO_3薄膜介电性能的影响

Effect of Mg-Doping on the Dielectric Behavior of Ba_(0.5)Sr_(0.5)TiO_3 Thin Films

用醋酸盐和钛酸四丁酯为原料,采用solgel工艺在Pt/TiO2/SiO2/Si基片上制备了含有Mg元素的Sr0.5Ba0.5xMgxTiO3薄膜,其退火处理温度为750℃。通过X射线衍射和扫描电镜分析技术研究了薄膜的相结构和形貌。采用美国HPAngilent4294A阻抗分析仪测试了以Pt为底电极、Ag为上电极的MFM电容器的介电性能。实验结果表明:掺镁Sr0.5Ba0.5xMgxTiO3薄膜较未掺杂的Ba0.5Sr0.5TiO3薄膜相对介电常数高、介电损耗低。介温谱表明在居里温度附近发生了弥散型相变,且居里温度有向低温方向漂移的趋势。

The microstructure and electrical properties of Mg-doped Ba0.5 Sr0. 5TiO3 thin films prepared by sol-gel processing using barium acetate, strontium acetate, magnesium acetate and titanium-tetrabutoxide as starting materials at a post deposition annealing temperature of 750℃ were reported in this paper. The structure and morphology of the films were analyzed by X-ray diffraction and SEM. The dielectrical measurements were conducted on metal-ferroelectric-metal capacitors using Pt as the bottom electrode and Ag as the top electrode. The Mg-doped Ba0. 5Sr0. 5TiO3 thin films exhibited improved dielectric constants and dielectric loss compared to undoped Ba0.5Sr0.5TiO3 thin films. The thin films exhibited dispersion phase transition at the Curie temperature which tended to shift to the lower temperature with the increasing Mg content. The high dielectric constant and low dielectric loss showed the application potential of Mg-doped Ba0.5Sr0.5TiO3 thin films for integrated capacitor and microwave communication devices.