中文摘要：

采用溶胶-凝胶法在Pt／Ti／SiO2／Si衬底上制备了多种不同组分的（Pb1-xSrx）TiO3（PST）（x=0．45、0．50、0．55、0．60、0．65）均匀薄膜和多层膜，并研究了它们的介电性质。发现均匀薄膜在x=0．55（PST55）时有最大的介电常数，10kHz下为879，损耗为0．029。在与均匀薄膜相同的条件下分别制备了PST45／PST55，PST50／PST60，PST55／PST653种多层膜。发现PST50／PST60多层膜的介电常数得到了明显的增强，在频率为10kHz时相对于同厚度的PST55均匀薄膜从879增加到1008，而损耗依然保持较低（0．027）。研究同时表明，PST多层膜在电容-电压可调谐性和介电击穿等性质方面也较均匀薄膜有不同程度提高。与其它两种多层膜比较后发现，在PST50／PST60多层膜中处于PST55左右组分的界面层对介电性质有比较大的影响。

英文摘要：

（Pb1-xSrx） TiO3 （PST） （x = 0.45,0. 50,0. 55,0. 60,0. 65） uniform and multilayered films on Pt/Ti/ SiO2/Si substrate were prepared by a sol-gel process and their dielectric properties were investigated. Among the uniform films, the PST55 （x= 0.55） film showed the maximum dielectric constant of εr =879 at 10kHz. Three types of multilayered films （PST45/PST55, PST50/PST60,PST55/PST65） were fabricated on the same conditions with the uniform films. The dielectric constant of the PST50/PST60 multilayered film was significantly enhanced compared with that of the uniform PST55 film. The dielectric constant of 1008 at 10kHz was observed at room temperature and the corresponding dielectric loss was kept as low as 0. 027. Corresponding to the uniform films, we also found that the multilayered films have improved C-V tunability and dielectric breakdown. Compared with the other two multilayered films, it has been indicated that the interface layer with the average component near PST55 in the PST50/PST60 multilayered film is the key-contribution to the dielectric enhancement.