【摘要】 在Si/SiO₂/Ti/Pt基片上用改进的溶胶-凝胶法制备了高掺杂浓度的Mg掺杂、K掺杂及Mg/K交替掺杂（K掺杂表层）的钛酸锶钡（BST）薄膜,并研究了其介电性能。X射线衍射（XRD）表明,薄膜为钙钛矿多晶结构。高浓度掺杂能细化晶粒、促进受主掺杂,K掺杂对应的晶化减弱,Mg掺杂对应的相当,交替掺杂对应的增强;随掺杂浓度增加,晶格常数和晶粒略有增大和细化;随层数增加,交替掺杂薄膜的晶格常数增大,晶粒细化,6层薄膜对应晶化最强。扫描电镜（SEM）表明,交替掺杂薄膜表面形貌介于两单掺杂薄膜之间,且随膜层增加由K掺杂形貌逐渐向Mg掺杂形貌转变;逐层制膜工艺和预晶化使截面形貌致密,且致密性随膜层增加而增加。C-V测试表明,K掺杂对应的调谐率和损耗最高,Mg掺杂对应的最低,交替掺杂对应的适中,且随掺杂浓度和/或膜层的优化而优化。更多还原

【Abstract】 Mg-doped, K-doped and Mg/K alternately doped BST films with high doped concentration have been prepared on Si/Si O2/Ti/Pt wafers by an improved sol-gel method. The dielectric properties of the films have been studied. XRD shows that the films exhibit cubic perovskite structures. High doped concentration is easy to refine the grains and promotes acceptor doping, but makes the crystallization of K doped BST film weak, that of Mg doped film equivalent and that of Mg/K-BST film enhanced. Mg/K-BST films show increasing lattice parameters and decreasing grains with increasing layer number, and 6-layer film corresponds to the strongest crystallization. SEM indicates that the surface morphologies of the alternately doped films are between those of K doped films and Mg doped films, and approach to those of Mg doped film with increasing layer number, and the cross-sectional SEM morphologies of the films are dense and getting denser with increasing layer number. C-V measurement reveals that tunability and dielectric loss of the K doped film are high, those of the Mg doped film are low, and those of the alternately doped film are moderate and optimized with the increasing doped concentration and/or layer number, meeting the needs of microwave tunable applications.更多还原