薄膜基底结构的振动理论与实验研究

发布时间：2018-05-11 23:01

本文选题：薄膜基底结构 + CGS光测实验技术　；参考：《兰州大学》2017年硕士论文

【摘要】：现代科学技术的迅猛发展,促使各类高度集成、多功能化的器件层出不穷。薄膜基底结构因具有这类特征日渐成为研究的热点之一,在微电子、光学、物理学和材料学研究领域得到了越来越广泛的应用,在集成电路、微机电系统(MEMS)等微器件方面的应用有力的促进了人类的生产生活。对于薄膜基底材料而言,通常由纳米尺度的薄膜和微米尺度的基底组合而成,其结构相对比较简单。由薄膜基底材料之间晶格常数不匹配产生的错配应变及外界非均温度分布引起的薄膜变形研究成为力学学科重要的研究方向之一。早在1909年,Stoney建立了薄膜应力与曲率之间的关系式,从而奠定了薄膜应力研究的基本框架,即通过薄膜曲率的测量来计算其全场应力分布。后来,大量学者通过放松Stoney基本假设实现了对Stoney公式的扩展,但是截至目前这些研究均主要考虑薄膜在准静态情形下的力学行为,而对于薄膜基底结构的振动特性研究鲜有涉及,成为薄膜基底结构器件安全设计所面临的困难。为此,本文建立了薄膜基底结构在轴对称和非轴对称情形下的自由振动方程,得到了薄膜应力关于曲率的解析表达式。随后,以高温超导薄膜为例,采用低温环境下激光剪切干涉(CGS)技术和本文所建立的薄膜应力与曲率之间的理论关系,首次获得了脉冲磁场作用后超导薄膜全场应力随时间的演化特征,为后期深入研究超导薄膜在电磁场中的力学响应提供了基础。本论文的主要工作如下:(1).通过考虑界面切应力,建立了薄膜基底结构在轴对称情形下自由振动方程,求得了薄膜应力关于曲率的解析表达式,并且针对振动方程,讨论了其挠度振型解以及相应固有频率。(2).通过考虑界面切应力,建立了薄膜基底结构在非轴对称情形下的自由振动方程,求得了薄膜位移表达式,应力表达式,界面切应力表达式,并且求给出了薄膜应力关于曲率的理论关系式。(3).利用低温下激光剪切干涉技术,实时测量了超导薄膜在受到电磁脉冲作用后的全场曲率变化,采用本文推导所得的薄膜曲率理论关系式,首次获得了超导薄膜全场应力随时间变化情况,并且针对测量结果做了相关分析以及讨论。
[Abstract]:With the rapid development of modern science and technology, various kinds of highly integrated and multifunctional devices emerge in endlessly. The thin film substrate structure has become one of the hotspots in the field of microelectronics, optics, physics and material science, and has been widely used in integrated circuits. The application of MEMS and other microdevices has greatly promoted the production and life of human beings. For thin film substrate, it is usually composed of nanoscale film and micron scale substrate, and its structure is relatively simple. The mismatch strain caused by the mismatch of lattice constants between the substrate materials and the deformation caused by the inhomogeneous temperature distribution have become one of the important research directions in the field of mechanics. As early as 1909, Stoney established the relationship between the stress and curvature of the film, thus laid a basic framework for the study of the film stress, that is to calculate the full field stress distribution by measuring the curvature of the film. Later, a large number of scholars extended the Stoney formula by relaxing the Stoney basic hypothesis, but up to now these studies have mainly considered the mechanical behavior of thin films under quasi-static conditions. However, the research on the vibration characteristics of the thin film substrate structure is seldom involved, which is the difficulty in the safety design of the thin film substrate structure device. In this paper, the free vibration equations of the thin film substrate structure under axisymmetric and non-axisymmetric conditions are established, and the analytical expression of the film stress on curvature is obtained. Then, taking the HTS thin film as an example, the laser shearing interference (CGS) technique at low temperature and the theoretical relationship between the stress and curvature of the thin film established in this paper are adopted. The evolution characteristics of the field stress with time after pulsed magnetic field are obtained for the first time, which provides a basis for the further study of the mechanical response of the superconducting film in the electromagnetic field. The main work of this thesis is as follows: 1. By considering the interfacial shear stress, the free vibration equation of thin film substrate structure under axisymmetric condition is established, and the analytical expression of the film stress about curvature is obtained, and aiming at the vibration equation, The deflection mode solution and the corresponding natural frequency are discussed. By considering the interfacial shear stress, the free vibration equation of the thin film substrate structure under the condition of non-axisymmetric is established, and the expressions of displacement, stress, interfacial shear stress are obtained. The theoretical relation of film stress on curvature is obtained. By using laser shearing interferometry at low temperature, the full-field curvature of superconducting films subjected to electromagnetic pulses was measured in real time. The theoretical formula of film curvature was derived in this paper. For the first time, the variation of the field stress with time is obtained, and the correlation analysis and discussion are made for the measured results.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O484.2

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