Temperature feedback control for improving the stability of a semiconductor-metal-oxide (SMO) gas sensor

• Published in: IEEE sensors journal Vol. 6; no. 1; pp. 139 - 145
• Main Authors: Jian-Wei Gong, Quan-Fang Chen, Ming-Ren Lian, Nen-Chin Liu, Daoust, C.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2006; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Ambient temperature; Circuit stability; Control systems; Control theory; Fabrication; Feedback; Feedback circuits; Feedback control; Feedback temperature control; Gas detectors; Gas sensors; Microelectromechanical systems; microelectromechanical systems (MEMS); Platinum; semiconductor-metal-oxide (SMO) sensor; Sensor systems; Sensors; sol gel; Stability; Temperature sensors; Tin
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2005.844353

Stability is a major concern of semiconductor-metal-oxide (SMO) gas sensors in practical applications, as they may cause false alarm problems. Ambient temperature is a major factor affecting the SMO gas sensor's stability. In this paper, we use a novel way to improve temperature stability of SMO (tin oxide) gas sensors by applying a temperature feedback control circuits which are compatible with our microelectromechanical systems sensor fabrication. A built-in platinum temperature sensor can precisely detect the sensor's working temperature. It provides feedback information to compensate the microheater's current to maintain the sensor's working temperature constant, regardless of ambient temperature change. Test results showed that, with this approach, significant improvement of stability has been achieved compared to SMO gas sensors without temperature compensation under the same ambient variation. The algorithm is realized through a hardware circuit, whose advantages include real time, large feedback gain, and low cost.