DocumentCode :
40198
Title :
A Miniaturized pH Sensor With an Embedded Counter Electrode and a Readout Circuit
Author :
Veeramani, M.S. ; Shyam, P. ; Ratchagar, N.P. ; Chadha, Anupama ; Bhattacharya, E. ; Pavan, Shanthi
Author_Institution :
Dept. of Electr. Eng., Indian Inst. of Technol. Madras, Chennai, India
Volume :
13
Issue :
5
fYear :
2013
fDate :
May-13
Firstpage :
1941
Lastpage :
1948
Abstract :
Electrolyte insulator semiconductor capacitors (EISCAPs) show a shift in the measured capacitance-voltage (C-V) characteristics with changes in the pH of the electrolyte and has the potential to be used as biosensors. The choice of an electrode to the EISCAP is important for reliable measurements. Here, we discuss a silicon-based EISCAP sensor bonded to a glass wafer with an embedded electrode. Three noble metal electrodes (Pt, Au, Ag) are studied for the ease of integration and performance and it is found that the chloridized Ag electrodes exhibit the highest pH sensitivity and the lowest electrode potential drift with time. A readout system that measures the pH of the electrolyte under test is developed and implemented in a programmable system on chip. Calibration of the EISCAP to account for sensor process variations is also incorporated. The pH measurement data on the miniaturized EISCAPs is presented.
Keywords :
biosensors; calibration; chemical sensors; electrochemical electrodes; electrolytes; glass; gold; pH measurement; platinum; readout electronics; silicon compounds; silver; supercapacitors; system-on-chip; Ag-Si; Au-Si; Pt-Si; biosensors; calibration; capacitance-voltage characteristics measurement; electrolyte insulator semiconductor capacitor; embedded counter electrode; glass wafer; metal electrode; miniaturized pH sensor; pH measurement; pH sensitivity; programmable system on chip; readout circuit; silicon-based EISCAP sensor; Capacitance-voltage characteristics; Electric potential; Electrodes; Glass; Gold; Sensitivity; Silicon; Biosensor; bonding; electrode integration; electrolyte insulator semiconductor capacitor (EISCAP); micromachining; miniaturization; pH sensing; thin film Ag-AgCl;
fLanguage :
English
Journal_Title :
Sensors Journal, IEEE
Publisher :
ieee
ISSN :
1530-437X
Type :
jour
DOI :
10.1109/JSEN.2013.2245032
Filename :
6428589
Link To Document :
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