A new measurement microphone based on MEMS technology

Scheeper, P.R.; Nordstrand, B.; Gullv, J.O.; Liu, Bin; Clausen, Thomas; Midjord, L.; Storgaard-Larsen, Torben

doi:10.1109/jmems.2003.820260

Cited by 102 publications

(52 citation statements)

References 7 publications

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“…The theoretical results obtained by this method were found to be in very good agreement with the experimental results reported in the case of a B&K MEMS microphone in Ref. 12. Very recently, Lavergne et al 13 developed a theory for electrostatic acoustical transducers used in environments and/or frequency ranges which are significantly different from those for which they have been designed according to the previous described work.…”

Section: Introductionsupporting

confidence: 79%

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An analytical-numerical method for determining the mechanical response of a condenser microphone

Homentcovschi

Miles

2011

The Journal of the Acoustical Society of America

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The paper is based on determining the reaction pressure on the diaphragm of a condenser microphone by integrating numerically the frequency domain Stokes system describing the velocity and the pressure in the air domain beneath the diaphragm. Afterwards, the membrane displacement can be obtained analytically or numerically. The method is general and can be applied to any geometry of the backplate holes, slits, and backchamber. As examples, the method is applied to the Bruel & Kjaer (B&K) 4134 1/2-inch microphone determining the mechanical sensitivity and the mechano-thermal noise for a domain of frequencies and also the displacement field of the membrane for two specified frequencies. These elements compare well with the measured values published in the literature. Also a new design, completely micromachined (including the backvolume) of the B&K micro-electro-mechanical systems (MEM) 1/4-inch measurement microphone is proposed. It is shown that its mechanical performances are very similar to those of the B&K MEMS measurement microphone.

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Section: Introductionsupporting

confidence: 79%

“…11 have N 0 ¼ 6 while the B&K MEMS (1/4 in.) measurement microphone described in the paper by Scheeper et al 12 has N 0 ¼ 4. Similar cases were considered by Petritskaya 6 and Tan and Miao 10 Therefore, it is sufficient to determine the pressure in a basic sector.…”

Section: B the Zero Order Solution For The Membrane Displacementmentioning

confidence: 99%

An analytical-numerical method for determining the mechanical response of a condenser microphone

Homentcovschi

Miles

2011

The Journal of the Acoustical Society of America

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“…[1][2][3][4] These microphones operate by sensing fluctuations in the separation between a fixed electrode and a flexible electrode induced by insonification of the flexible membrane. A bias is applied across the gap converting deflections of the sensing membrane to charge which is integrated by a preamplifier to give a voltage output.…”

Section: Introductionmentioning

confidence: 99%

Capacitively sensed micromachined hydrophone with viscous fluid-structure coupling

2005

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This work presents a novel design for a micromachined, capacitively sensed hydrophone. The design consists of a fluid-filled chamber constrained by two sets of membranes. The "input" membranes are arrayed around the outside of the circular chamber. Incoming sound generates a trapped cylindrical wave, creating mechanically amplified motion of the 1 mm diameter central "sensing" membrane. The membrane material is a LPCVD nitride/oxide/nitride triple-stack with respective film thickness 0.1/0.65/0.1 µm. The chamber is filled with 200 cSt viscosity silicone oil. Fluid-filling eases design constraints associated with submerging the sensor, especially with respect to exterior mass loading. Both silicon-glass anodic bonding and tin-gold solder bonding are used to form the structure, including the 5 µm sensing gap.The fluid-structure system is computationally modeled using both approximate analytic and numerical techniques. Model results indicate a 28 dB displacement gain between the motion of the "input" membranes and the "sensing" membranes. An off-chip charge amplifier, with a 10 pF integrating capacitor, is used to convert membrane motion into an electrical signal. Mean measured system sensitivity is 0.8 mV/Pa (-180 dB re 1 V/µPa) from 300 Hz-15 kHz with a 1.5 volt applied bias and a 26 dB preamplifier gain. The predicted low frequency sensitivity is 0.3 mV/Pa. The measured sensitivity exhibits considerable scatter below 7 kHz, with a standard deviation of 80%. Laser vibrometry measurements indicate that this scatter may be caused by compliance of the chip mounting scheme. Above 10 kHz, the quiescent noise is -100 dB re 1 V / √ Hz. Noise characteristics exhibit a 1/f character below 10 kHz, rising to a maximum of -50 dB re 1 V / √ Hz at 100 Hz.

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“…The piezoelectric and piezoresistive microphones have similar specifications; however, the piezoelectric microphone has the edge in terms of both dynamic range and bandwidth. Existing capacitive microphones possess a large dynamic range; however, they cannot measure up to 160 dB and their bandwidth is much too small for aeroacoustic measurements [9]. In the work, a dual-backplate capacitive microphone was developed at the University of Florida, fabricated using the SUMMiT V process at Sandia National Laboratories (SNL), and postprocessed at the University of Florida.…”

Section: Introductionmentioning

confidence: 99%

Compliant membranes for the development of MEMS dual-backplate capacitive microphone using the SUMMiT V fabrication process.

Martin

2005

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The objective of this project is the investigation of compliant membranes for the development of a MicroElectrical Mechanical Systems (MEMS) microphone using the Sandia Ultraplanar, Multilevel MEMS Technology (SUMMiT V) fabrication process. The microphone is a dualbackplate capacitive microphone utilizing electrostatic force feedback. The microphone consists of a diaphragm and two porous backplates, one on either side of the diaphragm. This forms a capacitor between the diaphragm and each backplate. As the incident pressure deflects the diaphragm, the value of each capacitor will change, thus resulting in an electrical output. Feedback may be used in this device by applying a voltage between the diaphragm and the backplates to balance the incident pressure keeping the diaphragm stationary.The SUMMiT V fabrication process is unique in that it can meet the fabrication requirements of this project. All five layers of polysilicon are used in the fabrication of this device. The SUMMiT V process has been optimized to provide low-stress mechanical layers that are ideal for the construction of the microphone's diaphragm. The use of chemical mechanical polishing in the SUMMiT V process results in extremely flat structural layers and uniform spacing between the layers, both of which are critical to the successful fabrication of the MEMS microphone.The MEMS capacitive microphone was fabricated at Sandia National Laboratories and postprocessed, packaged, and tested at the University of Florida. The microphone demonstrates a flat frequency response, a linear response up to the designed limit, and a sensitivity that is close to the designed value. Future work will focus on characterization of additional devices, extending the frequency response measurements, and investigating the use of other types of interface circuitry. 3ACKNOWLEDGEMENT

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A new measurement microphone based on MEMS technology

Cited by 102 publications

References 7 publications

An analytical-numerical method for determining the mechanical response of a condenser microphone

An analytical-numerical method for determining the mechanical response of a condenser microphone

Capacitively sensed micromachined hydrophone with viscous fluid-structure coupling

Compliant membranes for the development of MEMS dual-backplate capacitive microphone using the SUMMiT V fabrication process.

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