A pH-isfet and an integrated ph-pressure sensor with back-side contacts

Vlekkert, H.H. van den; Kloeck, B.; Prongué, D.; Berthoud, Jo¨rg; Hu, Bingmeng; Rooij, N. F. de; Gilli, Eduard; Crousaz, P de

doi:10.1016/0250-6874(88)80063-5

Cited by 50 publications

(8 citation statements)

References 23 publications

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“…Both structures have large cavities in one side so that some areas of the silicon chip are thinner and n-type regions can be formed that contact both sides of the chip. In some cases ( Figure 2a ) the ISFET gate is shaped on the flat side and the contacts are formed in the cavities [ 32 – 35 ], whereas in other cases ( Figure 2b ) the contacts are structured in the flat side and the ISFET gate is formed inside a cavity on the other side [ 36 – 38 ]. In order to achieve a better control of the silicon thickness in the cavity area Bond-and-Etch-back Silicon-On-Insulator (BESOI) wafers are often used [ 33 , 35 – 37 ].…”

Section: Technologies For Isfets Fabricationmentioning

confidence: 99%

ISFET Based Microsensors for Environmental Monitoring

Jimenez-Jorquera

Orozco

Baldi

2009

Sensors

152

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The use of microsensors for in-field monitoring of environmental parameters is gaining interest due to their advantages over conventional sensors. Among them microsensors based on semiconductor technology offer additional advantages such as small size, robustness, low output impedance and rapid response. Besides, the technology used allows integration of circuitry and multiple sensors in the same substrate and accordingly they can be implemented in compact probes for particular applications e.g., in situ monitoring and/or on-line measurements. In the field of microsensors for environmental applications, Ion Selective Field Effect Transistors (ISFETs) have a special interest. They are particularly helpful for measuring pH and other ions in small volumes and they can be integrated in compact flow cells for continuous measurements. In this paper the technologies used to fabricate ISFETs and a review of the role of ISFETs in the environmental field are presented.

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Section: Technologies For Isfets Fabricationmentioning

confidence: 99%

ISFET Based Microsensors for Environmental Monitoring

Jimenez-Jorquera

Orozco

Baldi

2009

Sensors

152

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“…Most attempts to utilize effects induced by the composition of the inner electrolyte have considered aqueous electrolytes containing analyte buffering or complexing ligands. The hydrogels can also be employed that resemble a scaled-down version of the inner electrolyte solution of the conventional ISE and have been used as an inner electrolyte for ISFETs, first reported in 1988 . Alternatively the ion-to-electron transduction function, normally achieved by the Ag/AgCl and inner solution, can be obtained by using a metal/carbon substrate, optionally modified with some other conducting material , including conducting polymers (CPs).…”

mentioning

confidence: 99%

“…The hydrogels can also be employed that resemble a scaled-down version of the inner electrolyte solution of the conventional ISE and have been used as an inner electrolyte for ISFETs, first reported in 1988. 32 Alternatively the ion-to-electron transduction function, normally achieved by the Ag/AgCl and inner solution, can be obtained by using a metal/carbon substrate, 33 optionally modified with some other conducting material 34,35 including conducting polymers (CPs). The latter CP approach has been considered using poly(pyrrole), [36][37][38][39][40] polythiopenes 41,42 and to a lesser extent polyanilines, 43,44 and poly(3,4-ethylenedioxythiophene).…”

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confidence: 99%

An Experimental Study of Membrane Materials and Inner Contacting Layers for Ion-Selective K⁺ Electrodes with a Stable Response and Good Dynamic Range

et al. 2004

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The goal was to identify formulations for use in valinomycin K(+) ion-selective electrodes that could routinely achieve a detection limit of <10(-6) M, even after repeated use and exposure at higher K+ activity (0.1 M) and without the requirement for special pretreatment or conditioning in low K+ activity (10(-3) M). Electrodes that would be characterized by high potential stability were sought in this work. Valinomycin-containing membranes with diffusion coefficient of approximately 10(-11) cm(2) s(-1), formulated from methacrylic/acrylic polymers with or without plasticizer, were compared with plasticized PVC membranes (diffusion coefficient 10(-8) cm(2) s(-1)). The methacrylic/acrylic membranes without plasticizer were shown to give an order of magnitude lower detection limit, when compared with PVC-dioctyl sebacate and o-nitrophenyl octyl ether plasticized methacrylic/acrylic polymers under the same conditions, highlighting the influence of plasticizer on the detection limit. As predicted from current theoretical derivation, the inner contacting layer in the ion-selective electrode construction was shown to be highly influential in maintaining the detection limit below 10(-6) M with use and with poly(pyrrole) providing the inner contact ion-to-electron transduction function, a further order of magnitude improvement in the lower detection limit could be maintained for both chloride and hexacyanoferrate doped poly(pyrrole), when 2% ionophore was employed in the ion-selective membrane. This formulation showed extraordinary stability and reproducibility in terms of measurement range and drift over extended measurement testing, with close to Nernstian slopes. At higher ionophore concentrations (4%), the apparent selectivity of the electrode was improved at the expense of detection limit and the nature of the poly(pyrrole) dopant ion became important in determining the dominant exchange processes at the poly(pyrrole)/ion-selective membrane interface.

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“…Electrical contact is made by heavily doped areas in this membrane. Some work has been presented on backside contacting of ISFET sensors [5][6][7][8]. Although slightly different in processing, they all rely on anisotropically wet etched holes and highly doped connections to drain and source contacts.…”

Section: Backside Contactsmentioning

confidence: 99%

“…[2][3][4][5][6][7][8][9][10][11][12] shows an anisotropically etched through-hole coated with Eagle photoresist before any baking treatment. The two close-ups show the obtuse and acute corners.…”

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confidence: 99%

Multiple Through-wafer Interconnects for MEMS Applications

Heschel

Kuhmann²,

Bouwstra³

2001

Sensors Update

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This chapter reports on the design and manufacturing of multiple through-wafer interconnects for stacking of microelectromechanical devices. The feedthroughs have been applied to an interconnect (intermediate) layer for an integrated microphone. The integrated microphone consists of the transducer part and an application specific integrated circuit (ASIC). The two parts are joined by stacking them on top of each other with the interconnect (intermediate) layer between them. The intermediate layer is a multifunctional layer. It provides the microphone with an acoustic frontchamber. The intermediate layer ensures the interchange of acoustical and electrical signals with the environment. Also, the intermediate layer protects the microphone during dicing, chip handling and in operation. The two active components are electrically connected through the intermediate layer by multiple wafer frontside to backside interconnects. The feedthrough interconnects are provided with under bump metallizations (UBM), solder bumps and sealing rings on the microphone side and top surface metallizations (TSM) on the ASIC side. The entire metallization system is based on electroplating techniques. The patterning of the metallizations has been done utilizing an electrodepositable photoresist (EDPR) as a plating mold. Several EDPR processes have been developed which are optimized for the respective metallization. The feedthrough interconnects have been optimized in terms of series resistance and parallel capacitance. Electrical characterization of the feedthrough interconnects has been carried out analytically and experimentally. The series resistance of one single interconnect wire is in the order of 100 mX. The parallel (parasitic) capacitance is in the order of 2 pF. Coupling between two adjacent feedthrough interconnects is negligible for low relative humidity (<50%). For high relative humidity (>90%) the impedance between two wires may be reduced due to a condensed water film. Sensitivity measurements performed before and after bonding of the interconnect layer to the microphone showed identical results which proves sufficient (TX) isolation between the feedthrough wires.

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A pH-isfet and an integrated ph-pressure sensor with back-side contacts

Cited by 50 publications

References 23 publications

ISFET Based Microsensors for Environmental Monitoring

ISFET Based Microsensors for Environmental Monitoring

An Experimental Study of Membrane Materials and Inner Contacting Layers for Ion-Selective K⁺ Electrodes with a Stable Response and Good Dynamic Range

Multiple Through-wafer Interconnects for MEMS Applications

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A pH-isfet and an integrated ph-pressure sensor with back-side contacts

Cited by 50 publications

References 23 publications

ISFET Based Microsensors for Environmental Monitoring

ISFET Based Microsensors for Environmental Monitoring

An Experimental Study of Membrane Materials and Inner Contacting Layers for Ion-Selective K+ Electrodes with a Stable Response and Good Dynamic Range

Multiple Through-wafer Interconnects for MEMS Applications

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Product

Resources

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An Experimental Study of Membrane Materials and Inner Contacting Layers for Ion-Selective K⁺ Electrodes with a Stable Response and Good Dynamic Range