Thin Film Bulk Acoustic Wave Devices. Performance Optimization and Modeling: Dissertation

    Research output: ThesisDissertationCollection of Articles

    Abstract

    Thin film bulk acoustic wave (BAW) resonators and filters operating in the GHz range are used in mobile phones for the most demanding filtering applications and complement the surface acoustic wave (SAW) based filters. Their main ad-vantages are small size and high performance at frequencies above 2 GHz. This work concentrates on the characterization, performance optimization, and mod-elling techniques of thin film BAW devices. Laser interferometric vibration measurements together with plate wave disper-sion modeling are used to extract the full set of elastic material parameters for sputter deposited ZnO, demonstrating a method for obtaining material data needed for accurate simulation of the devices. The effectiveness of the acoustic interference reflector used to isolate the vi-bration from the substrate is studied by 1-D modeling, 2-D finite element method and by electrical and laser interferometric measurements. It is found that the Q-value of reflector-based BAW resonators operating at 2 GHz is limited to approximately 2000 by mechanisms other than leakage through the reflector. Suppression of spurious resonances in ZnO resonators is studied in depth by modeling and measurements. It is verified that the approximate mode orthogo-nality is behind the suppression in boundary frame type ZnO devices operating in the piston mode, but also another narrow band mode suppression mechanism is found. A plate wave dispersion based 2-D simulation scheme for laterally acousti-cally coupled BAW resonator filters is developed and employed in designing of experimental devices, which show both good agreement with the model predic-tions and a remarkable 4.9 % relative bandwidth.
    Original languageEnglish
    QualificationDoctor Degree
    Awarding Institution
    • Aalto University
    Supervisors/Advisors
    • Kaivola, M., Supervisor, External person
    Award date25 Feb 2011
    Place of PublicationEspoo
    Publisher
    Print ISBNs978-951-38-7722-4
    Electronic ISBNs978-951-38-7723-1
    Publication statusPublished - 2011
    MoE publication typeG5 Doctoral dissertation (article)

    Fingerprint

    bulk acoustic wave devices
    optimization
    resonators
    acoustics
    reflectors
    thin films
    retarding
    filters
    vibration measurement
    wave dispersion
    pistons
    complement
    lasers
    narrowband
    finite element method
    leakage
    simulation
    bandwidth
    interference

    Keywords

    • thing film
    • bulk acoustic wave
    • BAW
    • AIN
    • ZnO
    • resonator
    • filter
    • GHz
    • microacoustic modeling
    • interferometric imaging

    Cite this

    @phdthesis{92d6efae5adf4d7890a5e1a3b64975a4,
    title = "Thin Film Bulk Acoustic Wave Devices. Performance Optimization and Modeling: Dissertation",
    abstract = "Thin film bulk acoustic wave (BAW) resonators and filters operating in the GHz range are used in mobile phones for the most demanding filtering applications and complement the surface acoustic wave (SAW) based filters. Their main ad-vantages are small size and high performance at frequencies above 2 GHz. This work concentrates on the characterization, performance optimization, and mod-elling techniques of thin film BAW devices. Laser interferometric vibration measurements together with plate wave disper-sion modeling are used to extract the full set of elastic material parameters for sputter deposited ZnO, demonstrating a method for obtaining material data needed for accurate simulation of the devices. The effectiveness of the acoustic interference reflector used to isolate the vi-bration from the substrate is studied by 1-D modeling, 2-D finite element method and by electrical and laser interferometric measurements. It is found that the Q-value of reflector-based BAW resonators operating at 2 GHz is limited to approximately 2000 by mechanisms other than leakage through the reflector. Suppression of spurious resonances in ZnO resonators is studied in depth by modeling and measurements. It is verified that the approximate mode orthogo-nality is behind the suppression in boundary frame type ZnO devices operating in the piston mode, but also another narrow band mode suppression mechanism is found. A plate wave dispersion based 2-D simulation scheme for laterally acousti-cally coupled BAW resonator filters is developed and employed in designing of experimental devices, which show both good agreement with the model predic-tions and a remarkable 4.9 {\%} relative bandwidth.",
    keywords = "thing film, bulk acoustic wave, BAW, AIN, ZnO, resonator, filter, GHz, microacoustic modeling, interferometric imaging",
    author = "Tuomas Pensala",
    note = "CA2: TK610 CA: Cluster1 OH: V{\"a}it{\"o}skirja SDA: MEL Project code: 70339 PGN: 97 p. + app. 73 p.",
    year = "2011",
    language = "English",
    isbn = "978-951-38-7722-4",
    series = "VTT Publications",
    publisher = "VTT Technical Research Centre of Finland",
    number = "756",
    address = "Finland",
    school = "Aalto University",

    }

    Thin Film Bulk Acoustic Wave Devices. Performance Optimization and Modeling : Dissertation. / Pensala, Tuomas.

    Espoo : VTT Technical Research Centre of Finland, 2011. 108 p.

    Research output: ThesisDissertationCollection of Articles

    TY - THES

    T1 - Thin Film Bulk Acoustic Wave Devices. Performance Optimization and Modeling

    T2 - Dissertation

    AU - Pensala, Tuomas

    N1 - CA2: TK610 CA: Cluster1 OH: Väitöskirja SDA: MEL Project code: 70339 PGN: 97 p. + app. 73 p.

    PY - 2011

    Y1 - 2011

    N2 - Thin film bulk acoustic wave (BAW) resonators and filters operating in the GHz range are used in mobile phones for the most demanding filtering applications and complement the surface acoustic wave (SAW) based filters. Their main ad-vantages are small size and high performance at frequencies above 2 GHz. This work concentrates on the characterization, performance optimization, and mod-elling techniques of thin film BAW devices. Laser interferometric vibration measurements together with plate wave disper-sion modeling are used to extract the full set of elastic material parameters for sputter deposited ZnO, demonstrating a method for obtaining material data needed for accurate simulation of the devices. The effectiveness of the acoustic interference reflector used to isolate the vi-bration from the substrate is studied by 1-D modeling, 2-D finite element method and by electrical and laser interferometric measurements. It is found that the Q-value of reflector-based BAW resonators operating at 2 GHz is limited to approximately 2000 by mechanisms other than leakage through the reflector. Suppression of spurious resonances in ZnO resonators is studied in depth by modeling and measurements. It is verified that the approximate mode orthogo-nality is behind the suppression in boundary frame type ZnO devices operating in the piston mode, but also another narrow band mode suppression mechanism is found. A plate wave dispersion based 2-D simulation scheme for laterally acousti-cally coupled BAW resonator filters is developed and employed in designing of experimental devices, which show both good agreement with the model predic-tions and a remarkable 4.9 % relative bandwidth.

    AB - Thin film bulk acoustic wave (BAW) resonators and filters operating in the GHz range are used in mobile phones for the most demanding filtering applications and complement the surface acoustic wave (SAW) based filters. Their main ad-vantages are small size and high performance at frequencies above 2 GHz. This work concentrates on the characterization, performance optimization, and mod-elling techniques of thin film BAW devices. Laser interferometric vibration measurements together with plate wave disper-sion modeling are used to extract the full set of elastic material parameters for sputter deposited ZnO, demonstrating a method for obtaining material data needed for accurate simulation of the devices. The effectiveness of the acoustic interference reflector used to isolate the vi-bration from the substrate is studied by 1-D modeling, 2-D finite element method and by electrical and laser interferometric measurements. It is found that the Q-value of reflector-based BAW resonators operating at 2 GHz is limited to approximately 2000 by mechanisms other than leakage through the reflector. Suppression of spurious resonances in ZnO resonators is studied in depth by modeling and measurements. It is verified that the approximate mode orthogo-nality is behind the suppression in boundary frame type ZnO devices operating in the piston mode, but also another narrow band mode suppression mechanism is found. A plate wave dispersion based 2-D simulation scheme for laterally acousti-cally coupled BAW resonator filters is developed and employed in designing of experimental devices, which show both good agreement with the model predic-tions and a remarkable 4.9 % relative bandwidth.

    KW - thing film

    KW - bulk acoustic wave

    KW - BAW

    KW - AIN

    KW - ZnO

    KW - resonator

    KW - filter

    KW - GHz

    KW - microacoustic modeling

    KW - interferometric imaging

    M3 - Dissertation

    SN - 978-951-38-7722-4

    T3 - VTT Publications

    PB - VTT Technical Research Centre of Finland

    CY - Espoo

    ER -