Micromachines 2016, 7(5), 74; doi:10.3390/mi7050074
A CMOS MEMS Humidity Sensor Enhanced by a Capacitive Coupling Structure
Key Laboratory of MEMS of the Ministry of Education, Southeast University, Sipailou 2, Nanjing 210096, China
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Author to whom correspondence should be addressed.
Academic Editors: Ching-Liang Dai and Nam-Trung Nguyen
Received: 14 December 2015 / Revised: 8 April 2016 / Accepted: 18 April 2016 / Published: 26 April 2016
(This article belongs to the Special Issue CMOS-MEMS Sensors and Devices)
Abstract
A capacitive coupling structure is developed to improve the performances of a capacitive complementary metal oxide semiconductor (CMOS) microelectromechanical system (MEMS) humidity sensor. The humidity sensor was fabricated by a post-CMOS process. Silver nanowires were dispersed onto the top of a conventional interdigitated capacitive structure to form a coupling electrode. Unlike a conventional structure, a thinner sensitive layer was employed to increase the coupling capacitance which dominated the sensitive capacitance of the humidity sensor. Not only static properties but also dynamic properties were found to be better with the aid of coupling capacitance. At 25 °C, the sensitive capacitance was 11.3 pF, the sensitivity of the sensor was measured to be 32.8 fF/%RH and the hysteresis was measured to be 1.0 %RH. Both a low temperature coefficient and a fast response (10 s)/recovery time (17 s) were obtained. View Full-TextKeywords:
CMOS MEMS; capacitive humidity sensor; nanowires; coupling electrode
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Huang, J.-Q.; Li, B.; Chen, W. A CMOS MEMS Humidity Sensor Enhanced by a Capacitive Coupling Structure. Micromachines 2016, 7, 74.
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