Novel concept for a MEMS microphone with dual channels for an ultrawide dynamic range

Kasai, Takashi; Sato, S.; Conti, Sebastiano; Padovani, Igino; David, Fillippo; Uchida, Yuki; Takahashi, T.; Nishio, Hidetoshi

doi:10.1109/memsys.2011.5734497

Cited by 9 publications

(6 citation statements)

References 4 publications

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“…The top plate, in this case, is fixed and cannot move, while the bottom plate is able to vibrate with the sound pressure, producing a variation of x (

) with respect to its steady-state value (

), proportional to the instantaneous pressure level (

). Different arrangements of the electrodes and fabrication solutions are possible [ 25 , 26 , 27 , 28 , 29 , 30 , 31 ], but the basic principle does not change.…”

Section: Capacitive Mems Microphonesmentioning

confidence: 99%

The Evolution of Integrated Interfaces for MEMS Microphones

Malcovati

Basçhirotto

2018

Micromachines

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Over the last decade, MEMS microphones have become the leading solution for implementing the audio module in most portable devices. One of the main drivers for the success of the MEMS microphone has been the continuous improvement of the corresponding integrated interface circuit performance in terms of both dynamic range and power consumption, which enabled the introduction in mobile devices of additional functionalities, such as Hi-Fi audio recording or voice commands. As a result, MEMS microphone interface circuits evolved from just simple amplification stages to complex mixed-signal circuits, including A/D converters, with ever improving performance. This paper provides an overview of such evolution based on actual design examples, focusing, finally, on the latest cutting-edge solutions.

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“…The top plate, in this case, is fixed and cannot move, while the bottom plate is able to vibrate with the sound pressure, producing a variation of x (

) with respect to its steady-state value (

), proportional to the instantaneous pressure level (

). Different arrangements of the electrodes and fabrication solutions are possible [ 25 , 26 , 27 , 28 , 29 , 30 , 31 ], but the basic principle does not change.…”

Section: Capacitive Mems Microphonesmentioning

confidence: 99%

The Evolution of Integrated Interfaces for MEMS Microphones

Malcovati

Basçhirotto

2018

Micromachines

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“…In addition to process technologies, various MEMS microphone designs are investigated for performance improvement such as signal-to-noise ratio (SNR), sensitivity and sensing range [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. By using the polysilicon-based condenser microphone as an example, the corrugated diaphragm has been employed to reduce the influence of residual stress so as to increase the microphone sensitivity [4,11].…”

Section: Introductionmentioning

confidence: 99%

Design and implementation of differential MEMS microphones using the two polysilicon processes for SNR enhancement

Chan

Wu³

et al. 2020

J. Micromech. Microeng.

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This study presents the design, fabrication and testing of the capacitive-type MEMS microphone with differential sensing electrodes to improve the sensitivity and signal-to-noise ratio (SNR). The microphone is designed and implemented based on an existing trench-refilled MOSBE process platform with two polysilicon structure layers, one Si3N4 electrical isolation layer and two sacrificial SiO2 layers. The microphone consists of top and bottom diaphragms and backplates. The top diaphragm and bottom backplate form a sensing electrode pair, and the bottom diaphragm and top backplate form the second sensing electrode pair. Moreover, the Si3N4 layer is exploited to partition the structures into three different electrical regions. Thus, the differential sensing MEMS microphone is achieved by using only two polysilicon structure layers. Various auxiliary components such as the central post and the U-shaped springs are also developed to realize the differential microphone. Measurements show that the typical fabricated microphone with a footprint of 800 μm diameter has the single-ended sensitivities of −45.8 and −47.2 dB (ref: 1 V/1 Pa), and the SNR is over 52 dB. Moreover, the ±3 dB bandwidth of the microphone ranges from 50 Hz–22 kHz. In summary, the presented microphone has the differential sensitivity of −40.5 dB (ref: 1 V/1 Pa) and the SNR of over 57.8 dB.

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“…Various diaphragm materials that have been used such as silicon nitride [15][16][17][18] silicon [19][20][21], polysilicon [22][23][24], aluminum [25][26][27] and polyimide [28]. However, the listed materials have their drawback such as the deformable silicon diaphragm due to the high processing process [29] and suffer from low sensitivity [5] and aluminum that require a pullin voltage of 105 V because of the high stiffness of the Al diaphragm [14].…”

Section: Introductionmentioning

confidence: 99%

Mechanical performance of SiC based MEMS capacitive microphone for ultrasonic detection in harsh environment

Zawawi¹,

Hamzah²,

Mohd-Yasin

et al. 2017

Nanoengineering: Fabrication, Properties, Optics, and Devices XIV

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In this project, SiC based MEMS capacitive microphone was developed for detecting leaked gas in extremely harsh environment such as coal mines and petroleum processing plants via ultrasonic detection. The MEMS capacitive microphone consists of two parallel plates; top plate (movable diaphragm) and bottom (fixed) plate, which separated by an air gap. While, the vent holes were fabricated on the back plate to release trapped air and reduce damping. In order to withstand high temperature and pressure, a 1.0 µm thick SiC diaphragm was utilized as the top membrane. The developed SiC could withstand a temperature up to 1400°C. Moreover, the 3 µm air gap is invented between the top membrane and the bottom plate via wafer bonding. COMSOL Multiphysics simulation software was used for design optimization. Various diaphragms with sizes of 600 µm 2 , 700 µm 2 , 800 µm 2 , 900 µm 2 and 1000 µm 2 are loaded with external pressure. From this analysis, it was observed that SiC microphone with diaphragm width of 1000 µm 2 produced optimal surface vibrations, with first-mode resonant frequency of approximately 36 kHz. The maximum deflection value at resonant frequency is less than the air gap thickness of 8 µm, thus eliminating the possibility of shortage between plates during operation. As summary, the designed SiC capacitive microphone has high potential and it is suitable to be applied in ultrasonic gas leaking detection in harsh environment.

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Novel concept for a MEMS microphone with dual channels for an ultrawide dynamic range

Cited by 9 publications

References 4 publications

The Evolution of Integrated Interfaces for MEMS Microphones

The Evolution of Integrated Interfaces for MEMS Microphones

Design and implementation of differential MEMS microphones using the two polysilicon processes for SNR enhancement

Mechanical performance of SiC based MEMS capacitive microphone for ultrasonic detection in harsh environment

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