Microphones

Fueldner, Marc

doi:10.1016/b978-0-12-817786-0.00048-7

Cited by 15 publications

(15 citation statements)

References 8 publications

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“…Graphene membranes cannot yet reach commercial values of THD, acoustic overload point (AOP = 140 dB SPL ) and dynamic range (105 dB SPL 31 ), also because they do not feature a doublebackplate configuration for differential readout which greatly reduces the THD and increases sensitivity. 36 The trade-off between sensitivity and dynamic range could be further optimized by better control over the membrane's stiffness.…”

Section: Discussionmentioning

confidence: 99%

“…The membranes in this work, like in several other graphene microphone publications, 18,22,23 do not satisfy this condition. However, it is important to note that depending on the target application, a bandwidth of 6-10 kHz can be sufficient, 22,36 therefore the reported low resonance frequency (<10 kHz) of graphene membranes is not necessarily limiting for their performance. Nevertheless, this problem could be compensated for in next generation devices by increasing their pretension n 0 or reducing the membrane radius R, while keeping competitive mechanical sensitivity.…”

Section: Discussionmentioning

confidence: 99%

“…We propose that given the high sensitivity of graphene one can further reduce the sensor's dimensions, increasing its resonance frequency, bandwidth and mechanical strength. Smaller sized membranes would also facilitate the implementation of arrays of membranes in parallel to increase SNR 36 or directionality and reduce effects of added air as well as squeeze film damping in closed cavity resonators with capacitive readout. 39 Therefore, we believe that graphene can indeed improve current microphone devices and that the main disadvantage and barrier to real applications lies in the lack of a more controllable fabrication method to suspend graphene membranes.…”

Section: Discussionmentioning

confidence: 99%

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Ultra-sensitive graphene membranes for microphone applications

et al. 2023

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Ultra-sensitive graphene membranes for microphone applications

et al. 2023

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“…Considerable research and development efforts during the last decades have led to tremendous improvements in the MEMS microphone architecture and application-specific integrated circuit (ASIC) read-out circuits [1][2][3] . From Eq.…”

Section: Introductionmentioning

confidence: 99%

Highly-sensitive wafer-scale transfer-free graphene MEMS condenser microphones

Pezone,

Anzinger,

Baglioni

et al. 2024

Microsyst Nanoeng

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Since the performance of micro-electro-mechanical system (MEMS)-based microphones is approaching fundamental physical, design, and material limits, it has become challenging to improve them. Several works have demonstrated graphene’s suitability as a microphone diaphragm. The potential for achieving smaller, more sensitive, and scalable on-chip MEMS microphones is yet to be determined. To address large graphene sizes, graphene-polymer heterostructures have been proposed, but they compromise performance due to added polymer mass and stiffness. This work demonstrates the first wafer-scale integrated MEMS condenser microphones with diameters of 2R = 220–320 μm, thickness of 7 nm multi-layer graphene, that is suspended over a back-plate with a residual gap of 5 μm. The microphones are manufactured with MEMS compatible wafer-scale technologies without any transfer steps or polymer layers that are more prone to contaminate and wrinkle the graphene. Different designs, all electrically integrated are fabricated and characterized allowing us to study the effects of the introduction of a back-plate for capacitive read-out. The devices show high mechanical compliances Cm = 0.081–1.07 μmPa−1 (10–100 × higher than the silicon reported in the state-of-the-art diaphragms) and pull-in voltages in the range of 2–9.5 V. In addition, to validate the proof of concept, we have electrically characterized the graphene microphone when subjected to sound actuation. An estimated sensitivity of S1kHz = 24.3–321 mV Pa−1 for a Vbias = 1.5 V was determined, which is 1.9–25.5 × higher than of state-of-the-art microphone devices while having a ~9 × smaller area.

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“…Considerable research and development efforts during the last decades have led to tremendous improvements in the MEMS microphone architecture and application-speciőc integrated circuit (ASIC) read-out circuits. [1][2][3] From Eq.1, to further improve microphone membrane compliance (C m ) and device sensitivity (S), membrane thickness and stress need to be reduced. Both physical properties generally limit the diaphragm compliance (C m ) and, as a result, also the device sensitivity S.…”

Section: Introductionmentioning

confidence: 99%

Highly-sensitive wafer-scale transfer-free graphene MEMS condenser microphones

Pezone,

Anzinger,

Baglioni

et al. 2023

Preprint

View full text Add to dashboard Cite

Since the performance of micro-electro-mechanical system (MEMS)-based microphones is approaching fundamental physical, design, and material limits, it has become challenging to improve them. Several works have demonstrated graphene’s suitability as a microphone diaphragm. The potential for achieving smaller, more sensitive, and scalable on-chip MEMS microphones is yet to be determined. To address large graphene sizes, graphene-polymer heterostructures have been proposed, but they compromise performance due to added polymer mass and stiffness. This work demonstrates the first wafer-scale integrated MEMS condenser microphones with diameters of 2R = 220 - 320 μm, thickness of 7 nm multi-layer graphene, that is suspended over a backplate with a residual gap of 5 μm. The microphones are manufactured with MEMS compatible wafer-scale technologies without any transfer steps or polymer layers that are more prone to contaminate and wrinkle the graphene. Different designs, all electrically integrated are fabricated and characterized allowing us to study the effects of the introduction of a back-plate for capacitive read-out. The devices show high mechanical compliances Sm = 0.081 - 1.07 μmPa−1 (10 - 100× higher than the silicon reported in the state-of-the-art diaphragms) and pull-in voltages in the range of 2 – 9.5 V. In addition, to validate the proof of concept, we have electrically characterized the graphene microphone when subjected to sound actuation. An estimated sensitivity of S1kHz = 24.3 - 321 mVPa−1 for a Vbias = 1.5V was determined, which is 1.9 - 25.5× higher than of state-of-the-art microphone devices while having a ∼ 9× smaller area.

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Microphones

Cited by 15 publications

References 8 publications

Ultra-sensitive graphene membranes for microphone applications

Ultra-sensitive graphene membranes for microphone applications

Highly-sensitive wafer-scale transfer-free graphene MEMS condenser microphones

Highly-sensitive wafer-scale transfer-free graphene MEMS condenser microphones

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