FET‐Based Chemical Sensor Systems Fabricated with Standard Technologies

Abstract

Miniaturized solid-state ion sensors based on field-effect transistors on silicon can take advantage of the capabilities of microelectronics and microsystems technology for the integration of combined functionalities. Optimized solidstate chemical sensors usually require specific materials and fabrication processes. However, if standard fabrication processes can be used, integrated chemical sensor systems can be developed in a shorter time and in a cost effective way. We show that, for applications in which a long operating time is not required, such as in disposable biomedical sensors, good integrated sensor systems can be fabricated with standard materials and processes. Specific examples are presented, such as multisensor systems, sensors with integrated signal-processing circuits and sensors with particle manipulation electrodes.

Immobilization of E. coli bacteria in three-dimensional matrices for ISFET biosensor design

“…Its sensitivity has been finally estimated at 50 mV/pH. This result is in accordance with those reported in the literature [35][36][37][38][39]. The dynamic potentiometric response of the ISFETs was studied by adding known aliquots of acid and base to a 25 ml of 0.1 M tris (hydroxymethyl)-aminomethane with an initial pH 9.4.…”

Chemical and Biological Field‐Effect Sensors for Liquids—A Status Report

“…Generally, the following basic mechanisms of potential generation can be considered: a pH or ion-concentration change, enzymatic reactions, adsorption of charged macromolecules (e.g., polyelectrolytes, deoxyribonucleic acid (DNA)), affinity binding of molecules (e.g., antigen-antibody affinity reaction, DNA hybridization), and potential changes that are coming from living biological systems as a result of more sophisticated (bio-)chemical processes (e.g., action potentials of nerve cells). [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] However, sometimes these results have been "rediscovered" from results that have already been obtained more than 10-30 years ago. At present, Si 3 N 4 , Al 2 O 3 , and Ta 2 O 5 serve as pH-sensitive gate insulator materials in commercial ISFETs.…”

Selective calcium ion detection with functionalized ZnO nanorods-extended gate MOSFET

“…The conversion of a FET into a sensing device normally involves the replacement of the metal gate electrode by a (bio) chemically sensitive interface (e.g. an analyte-selective membrane or an ion-conductive solution), which is brought in contact with the analyte solution (Errachid et al, 2004). Also present in or in conjunction with the analyte solution is a reference electrode, which completes the circuit via the gate voltage bias (Eggins, 2002;Schoning and Poghossian, 2002).…”