FBAR的应力负载效应研究

发布时间：2018-03-06 23:30

本文选题：应力负载效应　切入点：薄膜体声波谐振器　出处：《西南科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来随着薄膜体声波谐振器(FBAR)的发展,FBAR不仅在射频器件中表现出优秀的应用价值,在传感器领域的应用潜力也逐渐被挖掘出来,如FBAR微质量传感器、FBAR微加速度计、FBAR压力传感器等。FBAR微加速度计和FBAR压力传感器属于FBAR力学传感器一类,关于这类FBAR传感器的研究普遍存在一个问题——FBAR的敏感机理不详,也就是FBAR的应力负载效应的原因不详。针对这个问题展开了本文的工作,一方面深入研究FBAR的应力负载效应,另一方面,找到一种FBAR力学传感器的灵敏度计算方法。研究了FBAR的应力负载效应。从线性电弹理论出发推导了初应力下FBAR的阻抗表达式,研究了FBAR的谐振频率与初应力的关系,并通过ANSYS有限元软件仿真FBAR受集中力下谐振频率的变化,发现这两种情况下,FBAR的谐振频率偏移方向相反。通过第一性原理计算研究了Al N晶体的受不同压力下材料常数的变化,并通过理想FBAR的谐振频率计算方法粗略分析了不同受力条件下FBAR的谐振频率偏移情况,发现不同受力条件下FBAR的谐振频率变化趋势相同。提出了FBAR力学传感器灵敏度的计算模型或者方法。提出一种基于Mason模型的多尺度计算方法,采用第一性原理计算的压力与弹性常数之间的关系作为“桥梁”,连接Mason模型和结构力学有限元模型,采用微分-综合方法计算FBAR力学传感器的灵敏度。并在此基础上对该方法进行了改进,采用特征频率法求解FBAR的谐振频率,并用能量加权平均法求解FBAR结构中的平均压力和厚度方向的平均应变用于修正FBAR的材料参数和几何结构,进而计算FBAR力学传感器的灵敏度。讨论了基于电弹体非线性理论推导的摄动积分法。介绍了纯弹性摄动下FBAR的谐振频率偏移量的计算方法,考虑到纯弹性摄动计算方法的不足,没有考虑压电材料的压电和介电摄动,因此列出了考虑完整摄动的摄动积分方程。
[Abstract]:In recent years, with the development of thin film bulk acoustic resonator (FBARs), FBAR not only shows excellent application value in RF devices, but also has the potential of application in sensor field. For example, FBAR micro-mass sensor, FBAR micro-accelerometer, FBAR pressure sensor and so on. FBAR micro-accelerometer and FBAR pressure sensor belong to the FBAR mechanical sensor class. There is a general problem in the study of this kind of FBAR sensor, that is, the sensitive mechanism of FBAR is unknown. That is, the reason for the stress load effect of FBAR is unknown. The work of this paper is carried out in this paper. On the one hand, the stress load effect of FBAR is deeply studied, on the other hand, A method for calculating the sensitivity of FBAR mechanical sensor is found. The stress load effect of FBAR is studied. The impedance expression of FBAR under initial stress is derived from the linear electroelastic theory, and the relationship between the resonant frequency of FBAR and the initial stress is studied. ANSYS finite element software is used to simulate the change of resonant frequency of FBAR under concentrated force. It is found that the deviation direction of resonance frequency of FBAR is opposite in these two cases. The variation of material constants of AlN crystal under different pressures is studied by first-principle calculation. The resonance frequency offset of FBAR under different forces is roughly analyzed by the resonance frequency calculation method of ideal FBAR. It is found that the variation trend of resonance frequency of FBAR is the same under different loading conditions. A model or method for calculating the sensitivity of FBAR mechanical sensors is proposed. A multi-scale calculation method based on Mason model is proposed. The relationship between the pressure and elastic constants calculated by first principles is used as a "bridge" to connect the Mason model with the finite element model of structural mechanics. The sensitivity of FBAR mechanical sensor is calculated by differential-synthesis method, and the method is improved. The characteristic frequency method is used to solve the resonance frequency of FBAR. The average pressure and the average strain in the thickness direction of FBAR structure are solved by the energy weighted averaging method to modify the material parameters and geometric structure of FBAR. Then the sensitivity of the FBAR mechanical sensor is calculated. The perturbation integral method based on the nonlinear theory of the electro-elastic body is discussed. The calculation method of the resonance frequency offset of the FBAR under pure elastic perturbation is introduced, taking into account the shortcomings of the pure elastic perturbation calculation method. The piezoelectric and dielectric perturbation of piezoelectric materials is not considered, so the perturbation integral equations with holonomic perturbation are listed.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212;TN65

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