溶胶-凝胶法制备BaTiO_3/SrTiO_3多层膜的介电增强效应

Dielectric enhancement in sol-gel derived BaTiO_3/SrTiO_3 multilayered thin films

采用溶胶 凝胶法 ,在Pt Ti SiO2 Si衬底上逐层制备了BaTiO3 SrTiO3 多层膜 .从多层膜的XRD图可看出明显的双峰 ,分别对应为BaTiO3 和SrTiO3 的特征峰 ,表明样品已形成了多层膜结构 .与同厚度的Ba0 5Sr0 5TiO3 单层膜比较 ,BaTiO3 SrTiO3 多层膜的介电系数得到了明显的增强 ,在频率为 10kHz时 ,周期为 6 6nm的BaTiO3 SrTiO3 多层膜相对于同厚度的Ba0 5Sr0 5TiO3 薄膜的介电系数从 2 45增强到 5 95 ,而损耗依然保持较低 ,分别为 0 0 2 9和 0 0 33.研究同时表明 ,BaTiO3 SrTiO3 多层膜与单层膜的介电频率色散程度、C

Polycrystalline BaTiO 3/SrTiO 3 multilayered thin films have been prepared on Pt/Ti/SiO 2/Si substrates by a sol-gel processing.The X-ray diffraction patterns were composed of two sets of lines,one for BaTiO 3 and the other for SrTiO 3,indicating that the multilayered thin films were formed.The dielectric constant of the multilayered films was significantly enhanced and the dielectric loss kept low,compared with that of Ba 0.5Sr 0.5TiO 3 thin films.A maximum dielectric constant of 595 at 10kHz was observed for a stacking periodicity of 66nm at room temperature and the corresponding dielectric loss was kept low at 0.033.The study indicated that there are small differences between the multilayered films and the uniform films on the dielectric constant frequency dispersion,C-V characteristics and the dielectric constant-temperature relation.