Out-of-plane MEMS-based mechanical airflow sensor co-integrated in SOI CMOS technology

André, Nicolás; Rue, Bertrand; Scheen, Gilles; Flandre, Denis; Francis, Laurent; Raskin, Jean‐Pierre

doi:10.1016/j.sna.2013.11.017

Cited by 22 publications

(23 citation statements)

References 39 publications

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“…This displacement implies a variation of an electrical parameter. For instance, in [7] the authors developed a capacitive wall-shear stress sensor with the floating element displacement implying a capacitive variation, reflected in an electric potential variation; the authors in [8] simulated a cantilever-based flow sensor using the piezoresistance effect; and authors in [9] designed and manufactured capacitive airflow sensors based on out-of-plane cantilevers. These sensors present the clear advantage of a direct wall shear stress measurement.…”

Section: Figure 1: (A) Schematic Of a Flow Separation On An Airfoil Lmentioning

confidence: 99%

High temperature gradient calorimetric wall shear stress micro-sensor for flow separation detection

Ghouila-Houri

Gallas

Garnier

et al. 2017

Sensors and Actuators A: Physical

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The paper describes and discusses the design and testing of an efficient and high-sensitive calorimetric thermal sensor to measure simultaneously the magnitude and the direction of wall shear stress in aerodynamic flows. The main technical application targeted is the back flow and the flow separation detection for active flow control. The measurement principle is based on the flow-induced forced heat convection transfer on a heater element. The sensor is micro-structured with three parallel substrate-free wires presenting a high aspect ratio and supported by periodic perpendicular SiO2 micro-bridges ensuring a mechanical toughness and a thermal insulation relatively to the bulk substrate with high thermal inertia. The central wire is made of a multilayer structure (Au/TiSiO2/Ni/Pt/Ni/Pt/Ni/SiO2) and is composed of a heater element (Au/Ti) and a thermistor (Ni/Pt/Ni/Pt/Ni) enabling to measure the heater temperature. The upstream and downstream wires are thermistors enabling to operate in the calorimetric mode. This design provides a high temperature gradient and a homogeneous temperature distribution along the wires. The sensor operates in both constant current mode and constant temperature mode, with a feedback on current enabled by uncoupling heating and measure. Welded on a flexible printed circuit, the sensor was flush mounted on the wall of a turbulent boundary layer wind tunnel. The experiments, conducted in both attached and separated flow configurations, demonstrate the sensor sensitivity to the wall shear stress up to 2.4 Pa and the ability of the sensor to perform flow direction sensing for back-flow detection in a separated flow configuration.

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Section: Figure 1: (A) Schematic Of a Flow Separation On An Airfoil Lmentioning

confidence: 99%

High temperature gradient calorimetric wall shear stress micro-sensor for flow separation detection

Ghouila-Houri

Gallas

Garnier

et al. 2017

Sensors and Actuators A: Physical

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“…e l s e v i e r . c o m / l o c a t e / m e e achieved by magnetic lifting [22,23] or stress gradients [24,25]. In this research we have combined electrical connectivity with folding by capillary forces.…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

Capillary origami of micro-machined micro-objects: Bi-layer conductive hinges

Legrain¹,

Berenschot²,

Tas³

et al. 2015

Microelectronic Engineering

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Recently, we demonstrated controllable 3D self-folding by means of capillary forces of silicon-nitride microobjects made of rigid plates connected to each other by flexible hinges (Legrain et al., 2014). In this paper, we introduce platinum electrodes running from the substrate to the plates over these bendable hinges. The fabrication yield is as high as (77 ± 2)% for hinges with a length less than 75 μm. The yield reduces to (18 ± 2)% when the length increases above 100 μm. Most of the failures in conductivity are due to degradation of the platinum/ chromium layer stack during the final plasma cleaning step. The bi-layer hinges survive the capillary folding process, even for extremely small bending radii of 5 μm, nor does the bending have any impact on the conductivity. Stress in the different layers deforms the hinges, which does not affect the conductivity. Once assembled, the conductive hinges can withstand a current density of (1.6 ± 0.4) × 10 6 A/cm 2 . This introduction of conductive electrodes to elastocapillary self-folded silicon-based micro-objects extends the range of their possible applications by allowing an electronic functionality of the folded parts.

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“…Moreover, out-ofplane lateral structure [9,10,11] are difficult to fabricate and have a potentially high cost. Out-of-plane MEMS-based flow sensors have been reported by Andre et al [14] using capacitive readout mechanisms. However, the sensors are quite low sensitivity and temperature dependence due to the metal layer on bended beam electrodes.…”

Section: Introductionmentioning

confidence: 99%