Analysis and design of an electrostatic MEMS microphone using the PolyMUMPs process

Grixti, Ryan; Grech, Ivan; Casha, Owen; Darmanin, Jean Marie; Gatt, Edward; Micallef, Joseph

doi:10.1007/s10470-014-0484-9

Cited by 6 publications

(5 citation statements)

References 12 publications

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“…Torkkeli et al [56] reported that, as the volume of the back chamber increased from 0.8 to 100 mm 3 , the sensitivity of microphone went up to 4 mV/Pa. The same effect has recently been observed by Grixti et al [111].…”

Section: Volume Of Back Chambersupporting

confidence: 87%

A Review of MEMS Capacitive Microphones

et al. 2020

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This review collates around 100 papers that developed micro-electro-mechanical system (MEMS) capacitive microphones. As far as we know, this is the first comprehensive archive from academia on this versatile device from 1989 to 2019. These works are tabulated in term of intended application, fabrication method, material, dimension, and performances. This is followed by discussions on diaphragm, backplate and chamber, and performance parameters. This review is beneficial for those who are interested with the evolutions of this acoustic sensor.

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Section: Volume Of Back Chambersupporting

confidence: 87%

A Review of MEMS Capacitive Microphones

et al. 2020

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“…In addition, Table 8 shows a comparison with previous MEMS microphones. Our microphone has a sensitivity and bandwidth superior to the microphones reported in the literature [ 1 , 5 , 10 ] but has a lower SNR. The proposed design has a performance comparable with the commercial models; it was not possible to compare the internal dimensions due to the lack of information provided by the manufacturers.…”

Section: Resultsmentioning

confidence: 85%

“…[ 9 ] designed a MEMS capacitive microphone formed by a perforated aluminum diaphragm (500 µm × 500 µm × 3 µm). This microphone has a bandwidth up to 20 kHz and a sensitivity of 0.2 mV/Pa with a bias voltage of 105 V. Grixti et al [ 10 ] created a mathematical model of MEMS microphone composed by a clamped square diaphragm (675 µm × 675 µm), which is based on the PolyMUMPs process. This microphone is supplied by a voltage of 6 V, achieving a sensitivity of 8.4 mV/Pa and a cut-off frequency of 10.5 kHz.…”

Section: Introductionmentioning

confidence: 99%

Design and Modeling of a MEMS Dual-Backplate Capacitive Microphone with Spring-Supported Diaphragm for Mobile Device Applications

Peña-García

Aguilera-Cortés

González-Palacios

et al. 2018

Sensors

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New mobile devices need microphones with a small size, low noise level, reduced cost and high stability respect to variations of temperature and humidity. These characteristics can be obtained using Microelectromechanical Systems (MEMS) microphones, which are substituting for conventional electret condenser microphones (ECM). We present the design and modeling of a capacitive dual-backplate MEMS microphone with a novel circular diaphragm (600 µm diameter and 2.25 µm thickness) supported by fifteen polysilicon springs (2.25 µm thickness). These springs increase the effective area (86.85% of the total area), the linearity and sensitivity of the diaphragm. This design is based on the SUMMiT V fabrication process from Sandia National Laboratories. A lumped element model is obtained to predict the electrical and mechanical behavior of the microphone as a function of the diaphragm dimensions. In addition, models of the finite element method (FEM) are implemented to estimate the resonance frequencies, deflections, and stresses of the diaphragm. The results of the analytical models agree well with those of the FEM models. Applying a bias voltage of 3 V, the designed microphone has a bandwidth from 31 Hz to 27 kHz with 3 dB sensitivity variation, a sensitivity of 34.4 mV/Pa, a pull-in voltage of 6.17 V and a signal to noise ratio of 62 dBA. The results of the proposed microphone performance are suitable for mobile device applications.

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“…Even though the spring-capacitor system represents a good approximation for electrostatic transducers, a large-signal network model need not be based on this model, provided that an appropriate expression relating capacitance and deflection is found. Standard MEMS microphones [12], as well as CMUTs [13], are based on a membrane that bends upon application of an electric field, so the equation of a parallel-plate capacitor imposes certain limitations. A more recent development, the pull-in-free microphone from Ozdogan et al [25], is based electrostatic levitation and holds no resemblance to the springcapacitor system.…”

Section: B Generalisation Of the Capacitance And Electrostatic Forcementioning

confidence: 99%

“…Electrostatic MEMS microphones have already found widespread use [26]. Grixti et al [12] show the design of a diaphragmbased electrostatic MEMS microphone whose sensitivity has negligible temperature dependency (unlike traditional electret condenser microphones). Applications of this principle also extend to the ultrasound range, where capacitive micromachined transducers (CMUTs) have emerged as an interesting alternative to piezoelectric transducers [13], [14].…”

mentioning

confidence: 99%

Large-Signal Equivalent-Circuit Model of Asymmetric Electrostatic Transducers

Monsalve

Melnikov

Kaiser

et al. 2022

IEEE/ASME Trans. Mechatron.

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This article presents a circuit model that is able to capture the full nonlinear behavior of an asymmetric electrostatic transducer whose dynamics are governed by a single degree of freedom. Effects such as stressstiffening and pull-in are accounted for. The simulation of a displacement-dependent capacitor and a nonlinear spring is accomplished with arbitrary behavioral sources, which are a standard component of circuit simulators. As an application example, the parameters of the model were fitted to emulate the behavior of an electrostatic MEMS loudspeaker whose finite-element (FEM) simulations and acoustic characterisation where already reported in the literature. The obtained waveforms show good agreement with the amplitude and distortion that was reported both in the transient FEM simulations and in the experimental measurements. This model is also used to predict the performance of this device as a microphone, coupling it to a two-stage charge amplifier. Additional complex behaviors can be introduced to this network model if it is required.

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Analysis and design of an electrostatic MEMS microphone using the PolyMUMPs process

Cited by 6 publications

References 12 publications

A Review of MEMS Capacitive Microphones

A Review of MEMS Capacitive Microphones

Design and Modeling of a MEMS Dual-Backplate Capacitive Microphone with Spring-Supported Diaphragm for Mobile Device Applications

Large-Signal Equivalent-Circuit Model of Asymmetric Electrostatic Transducers

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