A CMOS-compatible monolithic conductivity sensor with integrated electrodes

Kordas, Norbert; Manoli, Yiannos; Mokwa, W.; Rospert, M.

doi:10.1016/0924-4247(93)00659-r

Cited by 12 publications

(5 citation statements)

References 8 publications

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“…Their robust and simple structure, their long term stability and reliability, and easy fabrication have attracted much attention from the sensor research community. Applications that have been proposed for these microelectrodes include measurement of the concentration of calcium [1], potassium [2], p(CO2) [3], pH [4], ethanol/methanol in gasoline [5], heavy metals [6], nitrate [7], urea [8][9], glucose [10], total prostate-specific antigen (PSA) [11], bacteria [12], red blood cells (hematocrit) [13], and detection of specific sequences of DNA [14]. In some applications, the measurement of a physical magnitude such as dielectric constant or conductivity of the media provides direct information of the analyte concentration [5,13].…”

Section: Introductionmentioning

confidence: 99%

“…In some applications, the measurement of a physical magnitude such as dielectric constant or conductivity of the media provides direct information of the analyte concentration [5,13]. In other applications, the deposition of a membrane or functional monolayer on top of the electrodes as a recognition element is necessary to obtain sensitivity and selectivity to particular species [1][2][3][4][6][7][8][9][10][11][12][13][14]. Different arrangements of electrodes (i.e.…”

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confidence: 99%

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Polysilicon interdigitated electrodes as impedimetric sensors

Rica

Fernández‐Sánchez

Baldi

2006

Electrochemistry Communications

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The suitability of polysilicon as a material for the fabrication of interdigitated electrodes and their application to the development of sensors is studied in this work. The main interest in using this material lies in the possibility of obtaining integrated sensors with commercial CMOS technologies and simple post-processing steps. Electrodes with 3μm finger width and 3, 10, and 20μm spacing were fabricated and characterised. Conductivity measurements in the range from 4 to 50μS/cm yielded a linear response with cell constants of 0.04cm prostate-specific antigen (PSA) [11], bacteria [12], red blood cells (hematocrit) [13], and detection of specific sequences of DNA [14]. In some applications, the measurement of a physical magnitude such as dielectric constant or conductivity of the media provides direct information of the analyte concentration [5,13]. In other applications, the deposition of a membrane or functional monolayer on top of the electrodes as a recognition element is necessary to obtain sensitivity and selectivity to particular species [1][2][3][4][6][7][8][9][10][11][12][13][14]. Different arrangements of electrodes (i.e. different number of electrodes and geometries) may be used for impedimetric measurements. Among them, interdigitated electrodes have significant advantages for certain applications: 1) their low cell constant (resistance to resistivity ratio) permit the measurement of very low conductivity solutions, 2) measurement of dielectric properties is possible thanks to a high inter-electrode capacitance (higher than stray capacitance even for conductive substrates), 3) the short penetration depth 3 of electric fields make them less dependent on the measurement cell geometry and allow the use of thin membranes for tailoring selectivity.In this paper the suitability of polysilicon as a material for the fabrication of interdigitated electrodes and their application to the development of sensors is studied. For example, the feasibility of measuring solution conductivity and permittivity with polysilicon electrodes is demonstrated. The main interest in using this material lies in the possibility of fabricating the electrodes with commercial CMOS technologies and simple post-processing steps, and therefore being able to integrate them as sensors in a more complex system-onchip. Another interesting advantage is that this material can be easily modified following a one-step silanisation reaction. In this way, robust immobilisation of either biomolecules or membranes can be carried out on to both the electrode fingers and the area in between them with the aim of developing a sensor device. As an example, a fully functionalised biosensor for the detection of urea is also presented.The basic structure of the interdigitated electrodes is depicted in Fig. 1. The polysilicon traces forming the interdigitated geometry are separated from the silicon substrate by a thick silicon dioxide layer. represented by R sol and C so l . From these components, the resistivity ρ (or the conductivity σ) and th...

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Polysilicon interdigitated electrodes as impedimetric sensors

Rica

Fernández‐Sánchez

Baldi

2006

Electrochemistry Communications

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“…Another approach is increasing the effective surface, for instance by platinization [16]. This method is counterproductive to integrated circuit technology, because a galvanic process would have to be included [17] into the sensor fabrication. To investigate these considerations, three different layouts of interdigitating electrodes …”

Section: Dimensioning Of the Electrolyte Conductivity Sensormentioning

confidence: 98%

Concept for a solid-state multi-parameter sensor system for cell-culture monitoring

Bäcker¹,

Beging²,

Biselli³

et al. 2009

Electrochimica Acta

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“…Different strategies have been used for the integration of these components. For example, electrodes for amperometric [ 3 ] and impedimetric [ 4 ] sensors have been typically integrated by noble metal deposition and lift-off process. High quality factor coils for power and data transmission in monolithic wireless systems have been integrated by electrodeposition of a thick copper layer in a photoresist mould and subsequent seed-layer etching [ 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

Towards Fully Integrated Wireless Impedimetric Sensors

Segura-Quijano

Sacristán-Riquelme

García-Cantón

et al. 2010

Sensors

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We report on the design and characterization of the building blocks of a single-chip wireless chemical sensor fabricated with a commercial complementary metal-oxide-silicon (CMOS) technology, which includes two types of transducers for impedimetric measurements (4-electrode array and two interdigitated electrodes), instrumentation circuits, and a metal coil and circuits for inductive power and data transfer. The electrodes have been formed with a polycrystalline silicon layer of the technology by a simple post-process that does not require additional deposition or lithography steps, but just etching steps. A linear response to both conductivity and permittivity of solutions has been obtained. Wireless communication of the sensor chip with a readout unit has been demonstrated. The design of the chip was prepared for individual block characterization and not for full system characterization. The integration of chemical transducers within monolithic wireless platforms will lead to smaller, cheaper, and more reliable chemical microsensors, and will open up the door to numerous new applications where liquid mediums that are enclosed in sealed receptacles have to be measured.

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A CMOS-compatible monolithic conductivity sensor with integrated electrodes

Cited by 12 publications

References 8 publications

Polysilicon interdigitated electrodes as impedimetric sensors

Polysilicon interdigitated electrodes as impedimetric sensors

Concept for a solid-state multi-parameter sensor system for cell-culture monitoring

Towards Fully Integrated Wireless Impedimetric Sensors

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