Improvement of the performance of microphones with a silicon nitride diaphragm and backplate

Scheeper, P.R.; Olthuis, Wouter; Bergveld, Piet

doi:10.1016/0924-4247(94)87003-9

Cited by 42 publications

(26 citation statements)

References 19 publications

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“…Condenser microphones include a rigid back plate, an air gap, and a flexible diaphragm, which vibrates with the sound pressure. The diaphragm is usually a silicon nitride [22] or a silicon [23], [24] membrane. In order to increase the microphone bandwidth, the back plate is sometimes perforated to reduce the streaming resistances in the air gap.…”

Section: A the Microphonesmentioning

confidence: 99%

Preliminary results on a silicon gyrometer based on acoustic mode coupling in small cavities

Bourouina

Exertier

Chaumet³

et al. 1997

J. Microelectromech. Syst.

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A silicon vibratory gas angular rate sensor has been developed by means of micromachining techniques. It is a shockproof sensor because it has no movable part. This device is a miniaturized form of an instrument, which has been previously fabricated in a conventional technology format and called the acoustic gyrometer. The working principle of this sensor is based on acoustic coupling between two orthogonal modes of a closed cavity, due to Coriolis forces effect on vibrating gas particles. The gyrometer, which is presented in this paper, was fabricated by a silicon process. It is constituted by an acoustic cavity and four microphones: one to generate an acoustic wave, one to slave the cavity at its first resonance frequency, and two for the measurement of the angular rate effect. Finiteelement modeling (FEM) modal analyses were performed on two cavity shapes: cylindrical and trapezoidal, corresponding to the fabricated devices. The results are compared with available analytic solutions and with measurements. [261]

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Section: A the Microphonesmentioning

confidence: 99%

Preliminary results on a silicon gyrometer based on acoustic mode coupling in small cavities

Bourouina

Exertier

Chaumet³

et al. 1997

J. Microelectromech. Syst.

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“…The damping, and thus the thermal-mechanical noise level, can be controlled by perforation of the membrane. This technique is already widely used in Si microphones to reduce squeeze film damping in order to gain bandwidth [7]. An improvement by a factor 100-1000 can be achieved without a significant loss of electrode area, due to fringe fields.…”

Section: Designmentioning

confidence: 99%

Bulk micromachined electrostatic RMS-to-DC converter

Graaf

Bartek²,

Xiao³

et al. 2001

IEEE Trans. Instrum. Meas.

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Abstract-Bulk micromachining in silicon and glass wafers and subsequent silicon-to-glass anodic bonding have been used for the realization of an electrostatic rms-to-dc converter. A suspended membrane has been designed for: large dynamic operating range (detection limit by minimum mechanical-thermal noise and high value of the pull-in voltage), maximum bandwidth (low series resistance, high second harmonic suppression using squeeze film damping and suspension beam design), long-term stability, and a sufficient displacement-to-voltage sensitivity (membrane area and suspension arm length). Index Terms-rms-to-dc converter, wafer-to-wafer bonding.

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“…[7][8][9][10][11][12] However, the traditional condenser microphones, with an acoustic slot around the circumference of the backplate and relatively fewer acoustic holes, have been widely accepted in the microphone industry because of their high performance, high reliability, and easy fabrication. Such design approach can also be adopted for MEMS microphones since the revolutionary deep reactive ion etch ͑DRIE͒ 13-16 and other bulk micromachining technologies can be utilized to realize their fabrication.…”

Section: Introductionmentioning

confidence: 99%

Analytical modeling for bulk-micromachined condenser microphones

Tan

Miao

2006

The Journal of the Acoustical Society of America

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The advent of silicon micromachining technology has opened up numerous opportunities for the commercialization of many miniaturized sensors and one of the beneficiaries is the silicon condenser microphone. Simple analytical expressions, such as those formulated by Škvor/Starr for mechanical-thermal noise calculation, are used to describe the mechanical performance of a microelectromechanical system ͑MEMS͒ microphone. However, the location effect of acoustic holes is usually not considered on both frequency response and mechanical-thermal noise. In this paper, the theory of a condenser microphone is reviewed and a new analytical modeling method for the MEMS condenser microphones is proposed based on Zuckerwar's model. With reference to a B&K MEMS microphone, the theoretical results obtained by the modeling method are in very good agreements with those experimental ones reported. It is also concluded that there is an optimum location for acoustic holes in the backplate. Finally, a new design for MEMS microphone with a polarization voltage of 10 V is proposed, which has an open-circuit sensitivity of 2.1 mV/ Pa ͑or −54 dB ref. 1 V / Pa͒, a bandwidth of 18 kHz, an A-weighted mechanical-thermal noise of 22 dB A, and a signal-to-noise ratio of 60 dB. This proposed microphone can be easily micromachined by using MEMS technology such as the deep reactive ion etching and wafer bonding technology.

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Improvement of the performance of microphones with a silicon nitride diaphragm and backplate

Cited by 42 publications

References 19 publications

Preliminary results on a silicon gyrometer based on acoustic mode coupling in small cavities

Preliminary results on a silicon gyrometer based on acoustic mode coupling in small cavities

Bulk micromachined electrostatic RMS-to-DC converter

Analytical modeling for bulk-micromachined condenser microphones

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