Chemical sensor as physical sensor: ISFET-based flow-velocity, flow-direction and diffusion-coefficient sensor

Flow-velocity Microsensors Based on Semiconductor Fieldeffect Structures

“…A typical response is linear between pH 2 and pH 12 with a slope of 55-58 mV/pH. For some experimental details, see [12][13][14].…”

“…As an alternative to flow sensors which apply the bubbles or oxygen-producing methods, recently, a new concept for a "time-of-flight"-type flow-velocity and flow-direction sensor that is based on in-situ electrochemical generation of ion tracers and an ISFET (ion-sensitive field-effect transistor) as iontracer detector, has been introduced and realised by the authors [12][13][14]. Such an ISFET-based flow sensor has a simple operation principle and uses a dynamic measuring method (i.e., only relative changes in the sensor's output signal are of interest and thus, the detector's drift, temperature instability and sensitivity discrepancy between the various ISFETs are not relevant).…”

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

“…In this approach, the same ISFET, which is well known as a (bio-)chemical sensor, also serves as a physical sensor and thus, the amount of obtained (bio-)chemical and physical information can be significantly higher than the number of sensors present in the system ("high-order" system). [76][77][78] On the basis of this concept, an ISFET-based multiparameter system for the detection of three (bio-)chemical (pH, K + , and penicillin concentration) and five physical quantities (temperature, flow velocity, flow direction, diffusion coefficient of ions, and liquid level) has been realized using only four ISFET transducers (see Figure 3). 13 Liquid-level sensor Figure 3.…”

Properties of AlN thin films deposited by means of magnetron sputtering for ISFET applications

“…ISFET microsensors were widely used for pH measurements [1][2][3], analytical and biomedical applications and monitoring of ground water pollution. ISFET is a good candidate for the investigation of various materials for new sensitive membranes.…”

“…Amorphous Si 3 N 4 is suitable only in a limited way, because its gate is subjected to a high drift and cannot be used in aggressive media for a longer period of time. The Si 3 N 4 -based devices show instability of the pH response caused by conversion of the nitride to a hydrated SiO 2 3 , were examined [1][2][3]. The reason for the introduction of alternative materials in silicon technology is primarily their high dielectric * E-mail: P.Firek@elka.pw.edu.pl constant, which can improve the detection properties of the devices.…”