Sensor systems for multi-parameter detection in fluidics usually combine different sensors, which are designed to detect either a physical or (bio-)chemical parameter. Therefore, such systems include a more complicated fabrication technology and measuring set-up. In this work, an ISFET (ion-sensitive field-effect transistor), which is well known as a (bio-)chemical sensor, is utilized as transducer for the detection of both (bio-)chemical and physical parameters. A multifunctional hybrid module for the determination of two (bio-)chemical parameters (pH, penicillin concentration) and three physical parameters (temperature, flow velocity and flow direction) using only two sensor structures, an ion generator and a reference electrode, is realized and its performance has been investigated. Here, a multifunctionality of the sensor system is achieved by means of different sensor arrangements and/or different operation modes. A Ta₂O₅-gate ISFET was used as transducer for all sensors. A novel time-of-flight type ISFET-based flow-velocity (flow rate) and flow-direction sensor using in-situ electrochemical generation of chemical tracers is presented. Due to the fast response of the ISFET (usually in the millisecond range), an ISFET-based flow sensor is suitable for the measurement of the flow velocity in a wide range. With regard to practical applications, pH measurements with this ISFET were performed in rain droplets.

Date Published: 22 February 2002
PDF: 11 pages
Proc. SPIE 4576, Advanced Environmental Sensing Technology II, (22 February 2002); doi: 10.1117/12.456950

Published in SPIE Proceedings Vol. 4576:
Advanced Environmental Sensing Technology II
Tuan Vo-Dinh; Stephanus Buettgenbach, Editor(s)