CONTROLE ELECTRIQUE DE LA RAIDEUR MECANIQUE PAR EFFET JOULE ET APPLICATION A UN MICRO-GYROMETRE VIBRANT

ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Microfabrication of high-density microelectrode arrays for in vitro applications

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Influence on moisture sensor performances, and characterization of different specific area porous silicon layers

This paper presents results obtained for characterization of porous silicon (PS) layers having different nanostructures, and the influence of this parameter on moisture sensor performances. Two PS layers have been studied, both present the same porosity of 45% and differ in their specific area: 330 m²/g for PS1 and 223 m²/g for PS2. Sorption isotherms were measured; the results justify the use of adsorption theories used to characterize mesoporous materials. Average values of pore diameter computed from adsorption theories and images processing show that PS1 presents smaller pores than PS2. Pore size distributions have been estimated, showing the wider distribution of PS2 compared with PS1. We measured resistivity of PS layers as a function of relative humidity (RH). We found that PS1 presents higher resistivity and higher relative variation of resistivity. Exposed to moisture step, PS1 sensor presents faster response time, showing a second advantage among performances criteria

Testing system-in-package wirelessly

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A New Technology of Ultrathin AlN Piezoelectric Sensor for Pulse Wave Measurement

International audienceIn this study the design and characterization of a new technology of ultrathin AlN piezoelectric sensors able to measure micro-deformations is reported. The sensors are fabricated using a CMOS compatible clean room process in which the sensitive part is embedded into a thin bio-compatible and conformal layer of parylene (total thickness below 10 µm). That makes the sensors very flexible and sensitive to micro-deformation measurements. In this study, this technology is applied to monitor heart activity: heart rate, blood pulse wave, pulse wave velocity. Blood pulse wave could be measured with a very good accuracy; this technology could thus be used for the prediction of cardiovascular diseases by analyzing the pulse wave shape

Towards New Low-Cost Multi-Sensor Systems

International audienceFor non-critical applications, consumer electronics requires more and more sensing components such as pressure sensors, accelerometers, magnetometers, flowmeters, microphones... Generally, each of these sensors is manufactured with a dedicated technology that involves specific materials and process flows together with either surface or bulk micromachining. The final multi-sensor system is then assembled on a PCB resulting in high manufacturing cost. In this paper, we propose an alternative where various MEMS-based sensors may be fabricated by direct bulk micromachining of the passive silicon substrate used for System-In-Package integratio

Kinetic Water Sorption by Porous Silicon Layers and Temporal Response of Moisture Sensors

International audienceThe experimental results obtained for kinetic water sorption by porous silicon (PS) layers and temporal response of moisture sensors based on these PS layers are presented in this paper. We studied two PS layers presenting equal porosity of 45 %, but differing in their nanostructure organization. PS1 presents a specific area of 330 m²/g and PS2 presents a specific area of 223 m²/g. We made resistive sensors deposing metallic contacts on PS layers surface; we measured the resistance variation of PS layers versus moisture level. The main result consists in the difference of time constant between kinetic water sorption and sensors temporal response. We represented the temporal response of kinetic water sorption which very longer than the temporal response of PS sensors. These results seem to confirm that mechanisms involved in sensors works occur at the PS layers surface; which is precious information in understanding of sensors functioning

Integrated saw filter into a silicon passive integration connecting substrate

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A SAW filter integrated on a silicon passive substrate used for system in package

International audienceA packaging method for dies containing an electro-mechanical component on a silicon substrate with a polymer seal ring is described in this paper. A Surface Acoustic Wave (SAW) filter, which is a kind of Micro Electro-Mechanical System (MEMS), is used as a capping substrate. Two different polymers are tested, Benzocyclobutene (BCB) and SU-8. The polymer and the assembly processes are described. The package has been characterized mechanically and the influence of the package on the electrical operation of the filter has been evaluated. A finite element thermo-mechanical analysis has been performed to simulate and understand the behaviour of this heterogeneous flip-chip package. This package enables to decrease the size of the assembly around 50% in term of thickness and footprint area without any electrical degradation compared to a stand-alone component

Processing of porous silicon surface images for the estimation of pore size distribution

International audienceThis abstract presents a method of pore size distribution (PSD) estimation based on images processing (IP). We de-veloped it using porous silicon (PS) layers having different nanostructures. PS1 presents a porosity of 45 % and a specific area of 330 m²/g; PS2 presents porosity of 45 % and specific area of 223 m²/g. We characterized the PS lay-ers by and Barrett-Joyner-Halenda (BJH) theories applied to sorption data. With BJH theory, we found that the mean pore diameter of PS1 and PS2 are respectively 4.3 nm and 5.5 nm. We performed images of PS layers surface by high resolution scanning electronic microscopy (HRSEM), the processing of theses images leaded to the estima-tion of mean pore diameter, 4 nm and 5 nm respectively for PS1 and PS2, and the representation of pore distribu-tion. Mean pore diameter obtained is closed to the value obtained with BJH theory, showing the validity of our method. Advantages of images processing are exposed