Modified Loss Mechanism of Mason Model for Bulk Acoustic Wave Resonators

Li, Qingwen; Li, Xiuping; Xie, Yuqiang; Cao, Zheyan; Dong, Jiarui

doi:10.1109/apmc52720.2021.9661849

Cited by 5 publications

(3 citation statements)

References 3 publications

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“…The Mason model [8] is a popular equivalent circuit model for designing FBARs. There are efforts to incorporate various loss mechanisms into the Mason model using a variety of approaches such as adding an imaginary part to each real material constant [9], adding additional acoustic branches for lateral modes [10], adding resistors to lump loss mechanisms [11], and incorporating ohmic loss by splitting the resonator into multiple branches of current sources connected through a grid of resistors and mapping the measured displacements to those individual branches of the Mason model [12]. There is an electro-thermo-mechanical model that verified that in BAW resonators, the 1D assumption of heat flow is valid [13].…”

Section: Introductionmentioning

confidence: 99%

Electrode Effects in mmWave Frequency Multilayer Bulk Acoustic Wave Resonators

Peng¹

2023

Preprint

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Electrodes are present in acoustic resonators to set electrical boundary conditions. Electrodes are acoustically part of a bulk acoustic wave (BAW) resonator that affect both its electromechanical coupling coefficient and its quality factor. Calculation of electromechanical coupling coefficient in multilayer structures requires the analysis of a system of equations relating the waves inside each layer to those in its adjacent layers. In this work, layer thicknesses and material constants in each layer are used to calculate the series and parallel resonance frequencies. Due to the proximity in frequency of series and parallel resonance, a series expansion of the series resonance frequency equation is performed around the parallel resonance frequency, and a closed form expression for electromechanical coupling coefficient from material constants and layer thicknesses is obtained to facilitate the observation of the electromechanical coupling coefficient effects of electrodes. Thermoelastic damping (TED) has been identified as the dominant acoustic loss mechanism in conductors. In this work, the complex wavenumber is calculated based on the unified theory of thermoelasticity to incorporate acoustic loss due to the interaction between elastic deformation and heat flow. Acoustic quality factors due to TED for common metals in microelectromechanical systems (MEMS) processing are calculated to facilitate the observation of the quality factor effects of electrodes. It is observed that there exists tradeoff among electromechanical coupling coefficient, acoustic quality factor, and electrical conductivity in the selection of electrode metals.

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Section: Introductionmentioning

confidence: 99%

Electrode Effects in mmWave Frequency Multilayer Bulk Acoustic Wave Resonators

Peng¹

2023

Preprint

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

Electrode Effects in mmWave Frequency Multilayer Bulk Acoustic Wave Resonators

Peng¹

2023

Preprint

View full text Add to dashboard Cite

Electrodes are present in acoustic resonators to set electrical boundary conditions. Electrodes are acoustically part of a bulk acoustic wave (BAW) resonator that affect both its electromechanical coupling coefficient and its quality factor. In this work, layer thicknesses and material constants in each layer are used to calculate the series and parallel resonance frequencies. For half wavelength per layer structures, a closed-form expression for electromechanical coupling coefficient from material constants is obtained to facilitate the observation of the electromechanical coupling coefficient effects of electrodes. Thermoelastic damping (TED) has been identified as the dominant acoustic loss mechanism in conductors. In this work, the complex wavenumber is calculated based on the unified theory of thermoelasticity to incorporate acoustic loss due to the interaction between elastic deformation and heat flow. Acoustic quality factors due to TED for common metals in microelectromechanical systems (MEMS) processing are calculated to facilitate the observation of the quality factor effects of electrodes. It is observed that there exists a tradeoff among electromechanical coupling coefficient, acoustic quality factor, and electrical conductivity in the selection of electrode metals.

show abstract

“…The Mason model [9] is a popular equivalent circuit model for designing FBARs. There are efforts to incorporate various loss mechanisms into the Mason model using a variety of approaches such as adding an imaginary part to each real material constant [10], adding additional acoustic branches for lateral modes [11], adding resistors to lump loss mechanisms [12], and incorporating ohmic loss by splitting the resonator into multiple branches of current sources connected through a grid of resistors and mapping the measured displacements to those individual branches of the Mason model [13]. There is an electro-thermo-mechanical model that verified that in BAW resonators, the 1D assumption of heat flow is valid [14].…”

Section: Introductionmentioning

confidence: 99%

Electrode Effects in mmWave Frequency Multilayer Bulk Acoustic Wave Resonators

Peng¹

2023

Preprint

View full text Add to dashboard Cite

Electrodes are placed in acoustic resonators to set electrical boundary conditions, and they inevitably are acoustically part of the structure for a bulk acoustic wave (BAW) resonator that affect both its electromechanical coupling coefficient and its quality factor. In this work, a modal analysis is performed to obtain a closed-form expression for electromechanical coupling coefficient from material constants. The impact on electromechanical coupling coefficient effects due to the characterstic acoustic impedance of electrodes is observed in half wavelength per layer structures. Thermoelastic damping (TED) has been identified as the dominant acoustic loss mechanism in conductors. In this work, acoustic quality factors due to TED for common metals in microelectromechanical systems (MEMS) processing are calculated to facilitate the observation of the quality factor effects of electrodes. It is observed that there are different strengths among characteristic acoustic impedance, acoustic quality factor, and electrical conductivity in different electrode metals.

show abstract

Modified Loss Mechanism of Mason Model for Bulk Acoustic Wave Resonators

Cited by 5 publications

References 3 publications

Electrode Effects in mmWave Frequency Multilayer Bulk Acoustic Wave Resonators

Electrode Effects in mmWave Frequency Multilayer Bulk Acoustic Wave Resonators

Electrode Effects in mmWave Frequency Multilayer Bulk Acoustic Wave Resonators

Electrode Effects in mmWave Frequency Multilayer Bulk Acoustic Wave Resonators

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