利用声子晶体减小锚点损耗的高频MEMS谐振器的性能研究

发布时间：2021-08-03 11:57

　　增强MEMS谐振器的性能是设计MEMS谐振器的主要目标。为了衡量谐振器的性能,可以用一系列的性能参来表征MEMS谐振器性能,包括谐振频率、品质因数、动态阻抗、非线性、功率容量和频率稳定性,这些参数可以用来衡量谐振器设计的好坏。这些参数中,高品质因素是一个提高谐振器性能的关键参数,并且在这些年的研究中被许多研究者提到过。锚点损耗是一种弹性波/声学波通过支撑梁从谐振体传导到基底产生的能量损耗。声学波通过支撑梁的耗散会减小谐振器中存储的能量,从而导致谐振器品质因数的降低。因此,锚点损耗是设计MEMS谐振器时常见的关键参数。减小锚点损耗可以提高谐振器的品质因数,从而提升谐振器的性能。一些已知的可以用于减小锚点损耗并提高谐振器品质因数（Q）的技术包括:支撑梁的优化;利用谐振腔将振动的能量集中在谐振体中;利用声子晶体将弹性波反射回谐振体并隔离谐振体与基底之间的弹性波/声学波的传播等。在这些技术中,声子晶体（PnCs）结构是一种广泛应用于减小MEMS谐振器锚点损耗的方法。利用一维（1D）声子晶体和二维（2D）声子晶体可以提供高的品质因数,但是一维声子晶体会使器件对机械振动十分敏感。这篇论文提供了一个... 

【文章来源】：电子科技大学四川省 211工程院校 985工程院校 教育部直属院校

【文章页数】：104 页

【学位级别】：硕士

【文章目录】：
摘要
ABSTRACT
Chapter 1 Introduction
    1.1 Research Background and Significance
    1.2 State of Arts
    1.3 Contents and motivations of thesis
    1.4 Outline of thesis
Chapter 2 Theoretical basics
    2.1 Piezoelectricity Theory and Piezoelectric MEMS Resonators
        2.1.1 Piezoelectricity: early application and principles
        2.1.2 Piezoelectricity: mathematical expression
        2.1.3 Types of piezoelectric materials
    2.2 Resonator mechanical-electrical model and equivalent electrical parameter
        2.2.1 One-port resonator model
        2.2.2 Two-port resonator Model
    2.3 Phononic Crystals
        2.3.1 Introduction
        2.3.2 Crystallography arrangement
    2.4 Theory of phononic crystals
        2.4.1 Energy band structure, Bloch theorem, theory and mechanism of openingband gap
        2.4.2 Phononic Crystals categories
    2.5 Phononic Crystal application in MEMS based devices
        2.5.1 Phononic Crystals-based support tethers configuration
        2.5.2 Phononic Crystals -based resonators
        2.5.3 Phononic Crystals-based waveguide and filters
    2.6 Reflectors
Chapter 3 Thin-film piezoelectric-on-substrate technology and simulation tools
    3.1 Introduction
    3.2 Piezoelectric on Substrate
    3.3 Figure-of-merit of performance of MEMS resonators
        3.3.1 Quality Factor
        3.3.2 Power Handling
        3.3.3 Resonant frequency
        3.3.4 Motional resistance
        3.3.5 Nonlinearity
        3.3.6 Frequency stability
    3.4 Thin-film-piezoelectric-on-silicon based MEMS resonators
    3.5 Total Quality factor and Anchor Quality Factor
    3.6 Energy loss mechanisms in MEMS resonator
        3.6.1 Anchor loss
        3.6.2 Thermo-elastic loss
        3.6.3 Electrode loss
        3.6.4 Interface loss
        3.6.5 Material loss
        3.6.6 Air loss
    3.7 Band gap, dispersion curves and power transmission spectra in PnC
    3.8 analysis tools for acoustic wave propagation and MEMS devices
        3.8.1 Plane Wave Expansion method
        3.8.2 Finite-Difference Time-Domain method
        3.8.3 Simulation tool based on finite element method (FEM)
    3.9 COMSOL Multiphysics
        3.9.1 Eigenfrequency analysis
        3.9.2 Frequency domain analysis
        3.9.3 Parametric sweep
Chapter 4 Designing and Simulation Results of Cross-shaped PnC for anchor lossreduction of thin-film ALN-on-silicon high frequency MEMS resonator
    4.1 Introduction
    4.2 Thin-film ALN-on-silicon high frequency MEMS resonator design
    4.3 Summary of design parameters
    4.4 Simulation results and discussion
        4.4.1 Eigenmode shapes of the resonators
        4.4.2 Band gaps in cross-shaped PnC structure
        4.4.3 Band gab calculation
        4.4.4 Quality factor of the resonators
        4.4.5 Harmonic response of the resonator
    4.5 T-shape PnC with lattice constant a=20μm
    4.6 T-shaped PnC with lattice constant a=5μm
    4.7 T-shaped PnC with lattice constant a=10μm
    4.8 Applying T-shape PnC on the Resonator
    4.9 Harmonic response of the resonator
    4.10 Conclusion
Chapter 5 Conclusions
    5.1 Concluding Remarks
    5.2 Future work
Acknowledgements
References
Research Result Obtained During the Study for Master Degree



本文编号：3319578