LaNiO_3缓冲层对Ba_(0.5)Sr_(0.5)TiO_3薄膜微结构和介电性能的影响

The Effects of LaNiO_3 Buffer Layer on the Microstructure and Dielectric Properties of Ba_(0.5)Sr_(0.5)TiO_3 Thin Films

利用射频磁控溅射法,在Pt/Ti/SiO2/Si和LaNiO3/Pt/Ti/SiO2/Si衬底上制备了Ba0.5Sr0.5TiO3薄膜.采用X-ray衍射（XRD）和原子力显微镜（AFM）,研究了两种衬底上BST薄膜样品的结晶性和表面形貌.结果表明：BST薄膜材料均为钙钛矿相,直接生长在硅衬底上的BST薄膜无择优取向,晶粒尺寸为20-30 nm,而LaNiO3缓冲层上生长的BST薄膜则为（100）择优取向,晶粒尺寸约为150-200 nm.室温下测试了薄膜的介电性能.研究结果表明,LNO缓冲层显著提高了BST薄膜的介电常数和介电可调率.

Ba0.5 Sr0. 5 TiO3 （BST） thin films were deposited on Pt/Ti/SiO2/Si and LaNiO3/Pt/Ti/SiO2/Si substrates by on-axis RF magnetron sputtering. X-ray diffraction （XRD） and atom force microscope （AFM） were used for microstrueture characterization of the samples. XRD spectra indicates that both BST films are entirely perovskite phase, while BST on Pt/Ti/SiO2/Si is polycrystal,BST on LNO/Pt/Ti/SiO2/Si is （100） preferential oriented. AFM indicates that the grain size of BST and BST on LNO are 20-30 nm and 150- 200 nm respectively. Capacity measurements were performed at 1 MHz at room temperature. It can be seen that the dielectric constant and tunability are greatly improved with the insertion of LNO buffer layer.