DocumentCode :
2027857
Title :
A digital CHEMFET front end
Author :
Al-Ahdal, Abdulrahman ; Toumazou, C.
Author_Institution :
EEE Dept., Imperial Coll. London, London, UK
fYear :
2012
fDate :
25-28 March 2012
Firstpage :
634
Lastpage :
636
Abstract :
Ion sensitive field effect transistors (ISFETs) have been used as analogue continuous time chemical sensors. Each ISFET had its own ion sensitive membrane as part of it. Allowing two ISFETs to share the same ion sensing membrane, a pH inverter was built. Chemical field effect transistors (CHEMFETs) are ISFETs´ derivatives. It is demonstrated here that using the ISFET based chemical switch it is possible to choose a chemical concentration threshold that when crossed the circuit changes state. A threshold of pH 6.75 was chosen and electrical output was shown to switch for pH changes from 6.5 to 7.0 and vice versa. This is effectively a digital CHEMFET basic building block as it serves as an input for further processing. This circuit can be used for chemical thresholding operations, as a digital CHEMFET transducer, in adverse applications including biomedical, chemical, and environmental industries.
Keywords :
chemical sensors; continuous time systems; invertors; ion sensitive field effect transistors; membranes; pH measurement; transducers; ISFET based chemical switch; analogue continuous time chemical sensors; biomedical industry; chemical concentration threshold; chemical field effect transistors; chemical industry; chemical thresholding operations; digital CHEMFET basic building block; digital CHEMFET front end; digital CHEMFET transducer; electrical output; environmental industry; ion sensing membrane; ion sensitive field effect transistors; ion sensitive membrane; pH inverter; Chemicals; Glass; Inverters; Logic gates; Semiconductor device modeling; Switches; Switching circuits;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Electrotechnical Conference (MELECON), 2012 16th IEEE Mediterranean
Conference_Location :
Yasmine Hammamet
ISSN :
2158-8473
Print_ISBN :
978-1-4673-0782-6
Type :
conf
DOI :
10.1109/MELCON.2012.6196511
Filename :
6196511
Link To Document :
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