Design and Electrochemical Characterization of Ion-Sensitive Capacitors With ALD Al2O3 as the Sensitive Dielectric

A process for the fabrication and further characterization of ion-sensitive capacitive sensors is reported. This process is based on a standard 5-μm complementary metal- oxide-semiconductor process, which has been designed to employ a single metal level. These sensors were fabricated with atomic lay...

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Bibliographic Details
Published in:IEEE sensors journal 2018-01, Vol.18 (1), p.231-236
Main Author: Molina-Reyes, Joel
Format: Article
Language:English
Subjects:
ALD
Aluminum oxide
Capacitance
Capacitive sensors
Capacitors
chemical and biological sensors
EIS sensors
Electric potential
Electrochemical analysis
Fabrication
Metal oxides
Sensitivity
Sensor phenomena and characterization
Sensors
Thin films
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Summary:A process for the fabrication and further characterization of ion-sensitive capacitive sensors is reported. This process is based on a standard 5-μm complementary metal- oxide-semiconductor process, which has been designed to employ a single metal level. These sensors were fabricated with atomic layer deposited thin films of Al 2 O 3 , used as the ion-sensitive dielectric. In addition, these devices were designed with a serial capacitive arrangement in order to provide an additional capacitive response. From the electrochemical characterization, it is shown that the capacitive sensors have a sensitivity in terms of the shift in the flat-band voltage of nearly 30-mV · pH -1 , and a sensitivity in the maximum capacitance displacement of 0.6-pF · pH -1 . It is shown that with these modifications, this kind of sensors are able to provide a response to the pH of a solution as a change in the maximum capacitance, or as a shift in the flat-band voltage while maintaining a simpler fabrication process in comparison with other technologies.
ISSN:1530-437X
1558-1748
DOI:10.1109/JSEN.2017.2754958