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Electrical Properties of Polysilicon Electrodes for Conductometric Measurement
Author(s) -
Wu Jian,
Suls Jan,
Sansen Willy
Publication year - 2000
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/(sici)1521-4109(200005)12:7<538::aid-elan538>3.0.co;2-m
Subject(s) - electrode , materials science , optoelectronics , analytical chemistry (journal) , chemistry , environmental chemistry
The miniaturized polysilicon electrodes for conductometric sensors have been fabricated by standard CMOS process. The interface impedance of polysilicon and saline solution (0.9 % NaCl) are measured in the frequency range of 100 Hz–1 MHz. At this frequency range, the impedance can be described as K /( (iω ) β , where K is around 33 MΩ Hz 0.93 and β is about 0.93 for the electrode area of 2 mm 2 . Compared to Pt black and Pt electrode, the impedance of polysilicon electrodes is quite large. This is supposedly due to the formation of silicon oxide layer at the surface of polysilicon electrodes in saline solution. The response of a pair of polysilicon electrodes to 0–75 mM KCl in saline solution at 20 KHz has good linearity. With the deposition of urease on the top of the pair of polysilicon electrodes, it is also possible to detect urea concentration with this conductometric setup.