BaTiO_3/SrTiO_3超晶格的微结构研究

Microstructural study of BaTiO_3/SrTiO_3 superlattice

本实验研究利用激光分子束外延法 (L%DMBE)研究在SrTiO3(STO) (0 0 1)基片上生长的BaTiO3(BTO) /SrTiO3(STO)超晶格的微结构 .利用小角X射线衍射光谱 (SAXRD)的计算机模拟来获得BaTiO3/SrTiO3 超晶格的微结构参数 ,如 :总的膜厚度、超晶格周期、表面和界面的均方根粗糙度等 .实验结果表明超晶格的表面和界面非常平整 ,均方根粗糙度大约为 0 .2nm .原子力显微镜 (AFM )的实验研究已经证明了超晶格结构的平滑程度 .超晶格的〈0 0

The microstructure of BaTiO 3 (BTO)/ SrTiO 3 (STO) superlattice grown on (001)SrTiO 3 substrate by laser molecular beam epitaxy (L MBE) was investigated. The microstructural parameters of BaTiO 3 / SrTiO 3 superlattice, such as the total film thickness, superlattice period, surface and interface root mean square (rms) roughness were obtained by computer simulation of the small angle X ray diffraction(SAXRD) spectra. The results show that the interfaces and surface of the superlattice are very smooth, their rms roughness is about 2 . The experimental examination by atomic force microscopy (AFM) has proved the smoothness of the surface of the superlattice. There exists a little correlation along <001> direction of the surperlattice. The growth mechanism of the superlattice was discussed. By modified Bragg law, the total thickness of the superlattice was calculated and is well consistent with that of the simulation of small angle X ray reflectivity.