A Review of MEMS Capacitive Microphones

Zawawi, Siti Aisyah; Hamzah, Azrul Azlan; Majlis, Burhanuddin Yeop; Mohd-Yasin, F.

doi:10.3390/mi11050484

Cited by 84 publications

(68 citation statements)

References 126 publications

(138 reference statements)

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“…Silicon-microfabricated free-standing membranes have been developed for several applications ranging from pressure sensors [10] to microphones [11] and microheaters [12]. Among the commercially available microfabricated membranes, some different options are available.…”

Section: Introductionmentioning

confidence: 99%

MEMS Membranes with Nanoscale Holes for Analytical Applications

Bagolini

Correale²,

Picciotto

et al. 2021

Membranes

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Micro-electro-mechanical membranes having nanoscale holes were developed, to be used as a nanofluidic sample inlet in novel analytical applications. Nanoscopic holes can be used as sampling points to enable a molecular flow regime, enhancing the performance and simplifying the layout of mass spectrometers and other analytical systems. To do this, the holes must be placed on membranes capable of consistently withstanding a pressure gradient of 1 bar. To achieve this goal, a membrane-in-membrane structure was adopted, where a larger and thicker membrane is microfabricated, and smaller sub-membranes are then realized in it. The nanoscopic holes are opened in the sub-membranes. Prototype devices were fabricated, having hole diameters from 300 to 600 nm, a membrane side of 80 μm, and a simulated maximum displacement of less than 150 nm under a 1 bar pressure gradient. The obtained prototypes were tested in a dedicated vacuum system, and a method to calculate the effective orifice diameter using gas flow measurements at different pressure gradients was implemented. The calculated diameters were in good agreement with the target diameter sizes. Micro-electro-mechanical technology was successfully used to develop a novel micromembrane with nanoscopic holes, and the fabricated prototypes were successfully used as a gas inlet in a vacuum system for mass spectrometry and other analytical systems.

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Section: Introductionmentioning

confidence: 99%

MEMS Membranes with Nanoscale Holes for Analytical Applications

Bagolini

Correale²,

Picciotto

et al. 2021

Membranes

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“…Microphones are used in a wide array of consumer products, such as smart phones, smart watches, laptops, headsets, and tablets [1]. Today, the most widely used type of microphone is the Micro Electro-Mechanical System (MEMS) microphone, as this type of microphone may have a long range of benefits over the alternatives [2].…”

Section: Introductionmentioning

confidence: 99%

“…The dominant contribution to noise in MEMS microphones is the squeezed-film effect [1], [4], which can be reduced by increasing the distance between the backplate and the diaphragm of the microphone. However, doing this will also reduce the signal strength, unless the bias voltage is increased as the air gap is increased.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Charge Pump Topologies for High Voltage Mobile Microphone Applications

Toft

Jørgensen

2021

ELEKTRON ELEKTROTECH

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This paper presents a novel analysis of charge pump topologies for very high voltage capacitive drive micro electro-mechanical system microphones. For the application, the size and power consumption are sought to be minimized, and a voltage gain of 36 is achieved from a 5 V supply. The analysis compares known charge pump topologies, taking into consideration on resistance of transistors and parasitic capacitances of transistors and capacitors in a 180 nm silicon-on-insulator process. The analysis finds that the Pelliconi charge pump topology is optimal for generating very high bias voltages for micro electro-mechanical system microphones from a low supply voltage when the power consumption and area are limited by the application.

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“…Beside the freestanding 3C-SiC cantilever, the use of a 3C-SiC diaphragm in MEMS sensors is equally important, especially for applications in extreme environments [1,4]. In terms of its use as an acoustic sensor, we performed a comprehensive literature review on the articles that published prototypes of MEMS microphones in the past 30 years [22]. We found that silicon carbide has never been employed as the acoustic diaphragm.…”

Section: Introductionmentioning

confidence: 99%

The Fabrication and Indentation of Cubic Silicon Carbide Diaphragm for Acoustic Sensing

et al. 2021

Self Cite

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In this study, 550 nm thick cubic silicon carbide square diaphragms were back etched from Si substrate. Then, indentation was carried out to samples with varying dimensions, indentation locations, and loads. The influence of three parameters is documented by analyzing load-displacement curves. It was found that diaphragms with bigger area, indented at the edge, and low load demonstrated almost elastic behaviour. Furthermore, two samples burst and one of them displayed pop-in behaviour, which we determine is due to plastic deformation. Based on optimum dimension and load, we calculate maximum pressure for elastic diaphragms. This pressure is sufficient for cubic silicon carbide diaphragms to be used as acoustic sensors to detect poisonous gasses.

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A Review of MEMS Capacitive Microphones

Cited by 84 publications

References 126 publications

MEMS Membranes with Nanoscale Holes for Analytical Applications

MEMS Membranes with Nanoscale Holes for Analytical Applications

Analysis of Charge Pump Topologies for High Voltage Mobile Microphone Applications

The Fabrication and Indentation of Cubic Silicon Carbide Diaphragm for Acoustic Sensing

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