Design and characterization of high sensitive MEMS capacitive microphone with fungous coupled diaphragm structure

Gharaei, Hassan; Koohsorkhi, Javad

doi:10.1007/s00542-014-2406-2

Cited by 19 publications

(12 citation statements)

References 24 publications

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“…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. Gharaei and Koohsorkhi [ 11 ] proposed an analytical model to design a MEMS microphone with a fungous-coupled diaphragm structure (460 µm diameter) that increased the diaphragm effective area, obtaining a parallel plates capacitor. This microphone has a pull-in voltage of 13 V, a sensitivity of 1.3 mV/Pa using a bias voltage of 11 V and a maximum frequency of 100 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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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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“…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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“…This device still has a lower sensitivity and needs to be decreased in size. Another design proposed in [90] has 5 holes with a diameter of 12 μm, each in the center of the membrane to reduce air trapping and improve the sensitivity and frequency response. They also showed that with the increase in membrane diameter, the effect of the center hole increases.…”

mentioning

confidence: 99%

“…When the membrane of a microphone is deflected, the effective area for the change in capacitance is decreased, causing the sensitivity to be decreased. To overcome this problem, the authors in [90] suggested two connected membranes as shown in Figure 7, in which the first part was exposed for acoustic wave while the second one, which is attached to the center of the first part, acts as a moving electrode. volume is, the poorer will be the sensitivity and frequency response [94].…”

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confidence: 99%

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Design Approaches of MEMS Microphones for Enhanced Performance

Shah

Lee

et al. 2019

Journal of Sensors

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This paper reports a review about microelectromechanical system (MEMS) microphones. The focus of this review is to identify the issues in MEMS microphone designs and thoroughly discuss the state-of-the-art solutions that have been presented by the researchers to improve performance. Considerable research work has been carried out in capacitive MEMS microphones, and this field has attracted the research community because these designs have high sensitivity, flat frequency response, and low noise level. A detailed overview of the omnidirectional microphones used in the applications of an audio frequency range has been presented. Since the microphone membrane is made of a thin film, it has residual stress that degrades the microphone performance. An in-depth detailed review of research articles containing solutions to relieve these stresses has been presented. The comparative analysis of fabrication processes of single- and dual-chip omnidirectional microphones, in which the membranes are made up of single-crystal silicon, polysilicon, and silicon nitride, has been done, and articles containing the improved performance in these two fabrication processes have been explained. This review will serve as a starting guide for new researchers in the field of capacitive MEMS microphones.

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Design and characterization of high sensitive MEMS capacitive microphone with fungous coupled diaphragm structure

Cited by 19 publications

References 24 publications

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

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

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

Design Approaches of MEMS Microphones for Enhanced Performance

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