用溶胶凝胶(Sol-Gel)法制备了三种钛酸锶钡(Ba0.6Sr0.4TiO3, BST)薄膜：常规的四层薄膜, 在逐层制备过程中，对首层薄膜进行中间热处理(Preheat-treatment, PT)的四层薄膜及间隔或交替地对奇数层薄膜进行中间热处理（称为交替中间热处理(Alternate-preheat-treatment, APT)）的八层薄膜. 用XPS研究薄膜表面成分化学态, 用SEM和AFM观察表面形貌及晶化, 并进行了介电性能测试. 结果表明, 常规薄膜介电性能差; 经PT, 薄膜裂纹和缩孔显著减少，形貌明显改善，表面非钙钛矿结构显著减少, 介电性能明显提高; 经APT, 薄膜形貌进一步改善，平均晶粒大小约30nm，非钙钛矿结构进一步减少, 介电损耗明显降低，介电稳定性和介电强度大幅度提高. APT为制备退火温度低及结构均匀致密的纳米晶BST薄膜提供了新方法, 可满足低频实用要求. 退火温度对薄膜厚度的影响也进行了讨论.
Normal four-layer-Ba0.6Sr0.4TiO3 (BST) films and two new types of BST films were prepared on Pt/Ti/SiO2/Si substrates by sol-gel method. For the first new type of films composed of four layers, the first layer was preheat-treated (PT) in the preparing process; while for the second new type of films consisted of eight layers, odd layers were alternate-preheat-treated (APT) in the preparing process. The effects of PT and APT on the dielectric properties of the BST films were studied. Scanning electron microscope (SEM) and atomic force microscope (AFM) were used to observe the film surface topography and particulate formation, X-ray photoelectron spectroscope (XPS) was performed to examine the film composition chemical states, and HP4284Atype LCR was employed to study the film dielectric properties. It is shown that the normal BST films display bad dielectric properties, whereas the BST films PT are smooth and compact with no crack or shrinkage cavity and significantly reduce surface non-perovskited structure, which indicates obviously the improvement of dielectric properties. Also, the BST films APT are more significantly improved in topographies, made up of nanocrystal grains about 30nm in average size and show more decrease of non-perovskited structure, and reveal lower dielectric loss and more enhanced dielectric stability and strength, satisfying actual application demands in low frequency field. In addition, the effects of annealing temperature and film thickness on the film structure and dielectric properties are discussed.
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