铈钇共掺钛酸锶钡薄膜的结构及介电性能

Structures and Dielectric Properties of CeY Codoping Barium Strontium Titanate Films

用改进的溶胶-凝胶法(sol-gel)制备了铈(Ce)钇(Y)共掺Ba0.6Sr0.4TiO3(BST)薄膜,研究了薄膜的结构和介电性能。扫描电镜(SEM)显示,共掺使薄膜致密、缩孔减少、晶粒大小均匀,随着共掺浓度的增加薄膜表面更平整光滑。原子力显微镜(AFM)表明,共掺薄膜表面致密、晶粒呈球状生长、晶界更明显,随共掺浓度的增加晶粒变小、表面粗糙度减小。V-C曲线表明,相对于铈或钇掺杂,共掺使薄膜的综合介电性能提高,2%Ce和2%Y共掺BST薄膜显示最佳的综合介电性能:零偏压下的电容为7.6×10-11F、介电损耗为0.0126,40V偏压下调谐率为41%,优质因子为32.5,可满足微波调谐器件的需要。

Cerium (Ce) and Yttrium (Y) codoped Ba0.6Sr0.4TiO3 (BST) films have been prepared on Pt/Ti/SiO2 /Si substrate by an improved sol-gel method. The structure and dielectric properties of the films have been studied. Scanning electron microscope (SEM) images show that codoping makes films compact and decreases shrinkage cavity, and the films have uniform grain size and become smoother with the increasing codoping concentration. Atomic force microscope (AFM) presents that codoped films show smooth surface with small roughness and small grain size with clear grain boundary with increasing codoping concentration. The V-C curves at 40 V and 100 kHz show that codoping improves the combination of dielectric properties. 2% Ce and 2% Y codoped BST thin film presents the best dielectric properties with capacitance 7.6×10 -11 F and dielectric loss (tanδ) 0.0126 at zero bias and tunability 41% and figure of merit 32.5 at 40 V, satisfying the needs of microwave tuned devices.