钛酸锶钡非线性铁电薄膜的尺寸效应研究

【作者】 赵莉；

【导师】 杨传仁；

【作者基本信息】 电子科技大学 ， 材料学， 2005， 硕士

【摘要】 本论文系统研究了Ba0.6Sr0.4TiO3(BST)薄膜的介电性质与薄膜微观结构、尺寸之间的依赖关系。首先本论文采用了射频磁控溅射技术(RF Magnetron Sputtering)在优化工条件下制备得到了光滑均一质量优良的BST 薄膜,研究了两种后处理(快速退火和管式炉退火)工艺对薄膜微结构的影响,讨论了退火温度对BST 薄膜的晶化、结晶取向、表面粗粗度、晶粒大小等的影响以及退火气氛、保温时间等其他因素对薄膜微结构的影响关系,并找到了控制薄膜尺寸的有效方法。进一步对薄膜的介电性能进行了研究,测得低频下薄膜介电常数为746,损耗1.7%。并测试了薄膜介电常数和损耗随频率与外加偏压的变化曲线。并对曲线做出了合理解释。在以上后处理研究基础上,继续研究了薄膜介电性能与薄膜尺寸之间的依赖情况。讨论了薄膜同一厚度下晶粒大小、薄膜厚度对介电性能的影响关系。结果表明:同一厚度下薄膜介电常数及其变化率随着晶粒的增大而不断增大;随着厚度的增加薄膜介电常数先增大后减小,变化率也各不相同,最薄时变化率最大,介电常数最大时变化率最小。更多还原

【Abstract】 In this thesis, the relationships of the dielectric properties with themicrostructures, thicknesses and grain sizes were studied.First, the BST thin films were prepared at the optimized parameters by RFmagnetron sputtering and annealed by two post treatments: RTA andtube-furnace. How the factors, temperature, atmosphere et al., of these postannealed methods influenced the microstructures (crystallization, orientation,roughness degree of surface, and the grain sizes) of BST thin films wasinvestigated. And the effective method of controlling grain sizes of BST thinfilms was got at last.Second, the dielectric properties of BST thin films was measured: thedielectric constant was 746,the loss tangent data was 1.7%.The cures of εr-f,D-f, εr-V were got and the reasons of why these cures were changed asthat manner were given and proved also.At last, based on the upward studies, the differences of the electricproperties of BST thin films which had different thicknesses and grain sizeswere experimented. The results are as follows:①the BST thin films of the samethickness, the larger the grain sizes, the higher the dielectric constant and △εwere;②with the increasing of thicknesses of BST thin films, the dielectricconstant was increased at first and appeared a maximum at 650nm, thendecreased; ③the △εwas also unequal at different thicknesses. Themaximum appeared at the thinnest films (260nm), the minimum at the filmswhich had the highest dielectric constant.更多还原