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Coordinator: Massimo Rudan
The objective is to demonstrate prototypes of an
intelligent analytical or olfactory microsensor system for monitoring volatile organic compounds (VOCs) in air.
The proposed system is a standard micronose chip (SMC) with capacitive, mechanical resonator,
thermopile microtransducers and signal conditioning, multiplexing, and analog-to-digital conversion circuits.
SMCs are made by CMOS IC technology combined with post-CMOS micromachining and film deposition. Several SMCs are
then flip-chip packaged on a ceramic substrate and coated with different VOC-sensitive polymers to form a
micronose module. The final goal is a complete hand-held microsystem including the micronose module and a
digital processing unit for analyte recognition, connected by a bus, and a serial interface for optional
connection to a personal computer.
The concept of the microelectronic nose or "micronose" is a miniaturized electronic nose based on
chemically-sensitive layers applied to silicon microtransducers compatible with silicon IC fabrication technology.
Regardless of miniaturization, an electronic nose consists of intake filters selecting analyte molecules, sensitive
layers turning analyte concentrations into physical signals, electronic transducers transforming physical into
electrical signals, electronic feature extraction and pattern recognition. The variation of intake structures,
sensitive materials (e.g., metal oxides, polymers, biomolecular functional systems), transduction effects
(e.g., resistive, capacitive, mass, spectral or thermal changes), transducer geometries and modulations
(e.g., frequency, bias voltage, temperature) allow for a vast number of chemical sensor features.
The miniaturization transforms the electronic nose into a micronose. Here the electronic transducer,
which converts physical or chemical signals into an electronic signal (or vice-versa), is manufactured
by silicon IC technology, notably CMOS technology, followed by IC compatible anisotropic etching and/or
film deposition after completion of the regular IC process. Mechanical, capacitive, and thermal
microtransducers cointegrated with signal conditioning circuits relevant to this research line have
been demonstrated. One proven advantage of integrating transducers and circuits on the same chip is the
detection of weak signals such as femto-Farad capacitive changes. Microtransducers are low in cost and
power consumption, fit everywhere, and are ready on demand for on-line monitoring.
In summary, the research line is meant to explore the merging of the electronic nose and microelectronics by
exploiting the overwhelming potential of microelectronics. By now, the objectives of the research line are
restricted to a few selected sensitive materials, microtransducers, and applications. Basing on the experience
gained from the activity, more challenging sensor materials such as components of biomolecular functional systems
(e.g., enzymes or receptors) and more demanding microtransducers such as acoustic-wave devices, may be tackled.
In view of its small size, low energy consumption, and low cost, the micronose initiated the transformation of
the previous, desktop size, electronic noses into a widely disseminated hand-held instrument or into distributed
on-line devices. With wider dissemination of the micronose, integration of the signal data processor unit on one
ASIC (application specific integrated circuit) chip becomes economical. Smaller size and lower price will, in turn,
open further applications, e.g., off-line quality control in the car, food, perfume, packaging, pharmaceutical, and
textile industries; on/in-line or spot-check process control in food, packaging, and textile industry; continuous
or discontinuous environmental analysis in industry and household.
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