Ba_(1-x)Sr_xTiO_3热释电梯度厚膜的制备和介电性能研究

Fabrication of Gradient Thick Film and Study on Dielectric Propertyof Pyroelectric Ba_(1-x)Sr_xTiO_3

钛酸锶钡(BST)组分梯度多层厚膜具有较好的综合介电性能,包括适中的介电常数、高的介电温度系数、低的介质损耗等,日益成为红外探测器、微波调制器件的重要候选厚膜材料。采用改进的溶胶-凝胶(Sol-Gel)法在Pt/Ti/SiO2/Si基片上制备Mn掺杂6层不同组分梯度BST厚膜,厚约5μm。研究了梯度BST厚膜的微观结构及其介电性能。X-射线衍射(XRD)分析表明,当热处理温度为750℃时,得到完整钙钛矿结构的厚膜材料。扫描电镜(SEM)电镜显示,厚膜表面晶粒大小均匀,排列紧密,致密性好,梯度BST厚膜的介电峰温区覆盖常温,介电常数峰值为920,介电损耗约为1.8×10-2。

The multilayer BST thick film with composition gradient is becoming the important alternative material for the infrared detector and microwave modulator due to its good comprehensive dielectric properties such as moderate dielectric constant and high dielectric-temperature coefficient,etc.In this paper,Mn-doped BST thick film with six different layers of composition gradients was fabricated in the Pt/Ti/SiO2/Si silicon chip by improved Sol-Gel method.The thick film was about 5 μm thick.Then the micro structure and dielectric property of the gradient thick film was studied.The XRD analysis showed that the thick film with complete perovskite structure could be obtained when the heat treatment temperature reached 750 ℃.The SEM microscope demonstrated that the surface grains had uniform size with dense arrangement and good density,and the dielectric peak temperature zone of the gradient BST thick film covered the normal temperature with dielectric coefficient 920 and dielectric loss approximately 1.8×10-2.