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多元氧化物薄膜,特别是ABO_3钙钛矿结构的薄膜由于有铁电、压电、热释电和超导等特性和在多功能电子器件上的广泛应用而成为电子功能材料研究的热点．该文利用激光分子束外延和磁控溅射等薄膜制备技术,采用反射式高能电子衍射(RHEED)对薄膜的生长进行原位实时的检测分析,确定了在不同的工艺条件下氧化物薄膜的层状、层岛混合和岛状生长模式。优化了薄膜的生长条件,实现了对薄膜生长模式的有效控制,绘制出SrTiO_3、BaTiO_3等薄膜的生长模式图谱。测量计算了薄膜的表面活化能和沉积粒子在表面的有效扩散率,发现氧化物薄膜表面的生长运动单元具有活化能小、迁移时间长等重要特点,采用原子力显微镜(AFM)和掠入射XRD对层状生长薄膜的层厚结构进行了精细测量,提出了氧化物薄膜单胞生长动力学模型,即薄膜生长的主要单元是以B-O八面体为主体的单原胞基团．在此基础上,系统地研究了薄膜生长异质界面应力释放行为和对结构性能的影响,在小失配度、中等失配度和大失配度下体现出的不同生长规律,出现了在临界厚度下的相干外延、应变岛、双晶外延和近重位点阵等现象．最后,通过薄膜和衬底的失配度的选择来调整界面应力的影响,并通过工艺条件来诱导薄膜结构取向,如采用薄膜自外延技术和自缓冲层技术,有效地控制和大幅度改善了铁电薄膜、介电薄膜、超导薄膜和热释电薄膜的微结构和电磁性能。
Multi-oxide films, especially ABO 3 perovskite films, have been the focus of electronic functional materials due to their characteristics of ferroelectric, piezoelectric, pyroelectric and superconductivity and their wide application in multifunctional electronic devices. In this paper, by means of laser molecular beam epitaxy and magnetron sputtering and other thin film preparation technology, using the reflection of high energy electron diffraction (RHEED) film growth in situ detection in situ analysis to determine the oxide film under different process conditions Layered, island-island hybrid and island-shaped growth patterns. The growth conditions of the films were optimized, and the effective control of the film growth mode was achieved. The growth pattern of SrTiO_3 and BaTiO_3 films was drawn. The surface activation energy of the film and the effective diffusivity of the deposited particles on the surface were measured and calculated. It was found that the growth kinetic elements on the surface of the oxide thin film had the characteristics of small activation energy and long migration time. The atomic force microscopy (AFM) and grazing incidence XRD The layer thickness structure of the layered growth thin film was finely measured, and the kinetic model of the growth of the oxide thin film was proposed. That is, the main unit of the thin film growth was a mono-primordial group mainly composed of the octahedron of octahedron. On this basis, we systematically studied the stress release behavior and the influence on the structure and properties of the heteroepitaxial interface. The different growth patterns under small mismatch degree, moderate mismatch degree and large mismatch degree appeared in Coherent extension of critical thickness, strain islands, twinning and near-heavy lattice. Finally, the effect of interfacial stress is adjusted by the choice of mismatch between the film and the substrate, and the orientation of the film structure is induced by the process conditions, such as the film self-epitaxy technology and self-buffer technology, which effectively controls and greatly improves Ferroelectric thin films, dielectric films, superconducting films and pyroelectric thin films of the microstructure and electromagnetic properties.