Microphone with Planar Nano-Gauge Detection: Fluid-Structure Coupling Including Thermoviscous Effects

Abstract

To cite this version:Thierry Verdot, Emmanuel Redon, Kerem Ege, Jaroslaw Czarny, Cécile Guianvarc'H, et al.. Microphone with planar nano-gauge detection: fluid-structure coupling including thermoviscous effects. Acta Acustica united with Acustica, Hirzel Verlag, 2016, 102 (3) AbstractThis article presents the modeling of a MEMS microphone with an original architecture formed of mechanical structures moving in the plane of the substrate. On the contrary of most microphones generally constituted of an oscillating membrane, some transducers developed by the CEA-LETI with M&NEMS technology use micro beams moving in the plane of the silicon wafer under the effect of an acoustical wave. These micro-structures are connected to the substrate by flexible micro-hinge and strain silicon nano-gauge producing a variation in resistance by piezoresistive effect. After the description of the design and functioning of the microphone under study, the vibroacoustic model of the fluid-structure coupling is presented. Considering the dimensions of the MEMS transducer close to the thermal and viscous boundary layers thicknesses, this model has to include diffusion phenomena. The model is discretized using the finite element method and the weak formulation is implemented using COMSOL Multiphysics® software. The pressure sensitivity of the microphone is calculated and compared with an analytical lumped model to asses the numerical model. Pressure and velocity fileds are also computed. Solutions of simulations are interpreted by focusing on phenomena influencing the sensitivity of this novel sensor design. In particular, the influence of the geometry and the role of the different part of the transducer (back cavity, mechanical structures) are studied.

Silicon Nanowires Driving Miniaturization of Microelectromechanical Systems Physical Sensors: A Review

“…It is found that the volume of the back cavity is the most critical parameter that affects the sensitivity. [135,136] In a subsequent study, a 0.28 μm CMOS integrated circuit is implemented as the readout circuit together with an analog-to-digital converter (ADC) based on a 1-bit Sigma delta modulator. As a result, a noise density of 7 nV Hz À1/2 in the frequency range from 10 Hz to 10 kHz is achieved.…”

Modeling of MEMS Transducers with Perforated Moving Electrodes

“…Note that such MEMS structures can be employed in other domains than audio, such as energy transfer, energy harvesters, and resonators [ 9 , 10 , 11 ]. However, new designs presenting technological advances have been proposed recently in the literature, such as a microphone with moving microbeam [ 12 ], or transducers (sources and microphones) with perforated moving electrodes. The mean motivation for the work presented herein is the latter case with electrodes in the form of elastic perforated plates clamped at all boundaries [ 13 ] or rigid elastically supported perforated plates [ 14 , 15 , 16 , 17 ].…”

Coulomb actuated microbeams: A Chebyshev-Edgeworth approach to highly efficient lumped parameter models

“…Coulomb-actuated microbeams play a crucial role in many Micro-Electro-Mechanical Systems (MEMS) applications [1][2][3] . They enable actuation using electrostatic forces and capacitive sensing, give rise to pioneering applications in medicine 4 , communications 5,6 , sensing 2,7 , and consumer products [8][9][10][11][12] . To meet the needs of recent developments, such as 5G Internet of Things (5G-IoT) 6 , augmented reality 13 , and Green ICT (information and communications technology) 14,15 , a system level consideration of a high number of electro-mechanical components is necessary.…”