Dual MOSFET Hydrogen Sensors with Thermal Island Structure

Abstract:

A low powered hydrogen gas sensor of the FET (field-effect transistor) structure was designed, fabricated and characterized for self-compensation to outer environments. The dual-gate FET hydrogen sensor was integrated with a micro-heater and two Pt-gate FETs; a sensing device for hydrogen detection, and a reference device as an electrical compensator. The identical output between the sensitive-FET and reference-FET was stable at temperatures ranging from room temperature to 250°C due to the same temperature dependence of the currentvoltage (IV) characteristics. The Pt-FET sensor showed stable responses to hydrogen at a range of operation temperatures. The optimal point in the micro-heater operation for 5,000 ppm H₂ gas injection was approximately 150°C. The highest sensitivity was 0.112 mA, and the response and recovery times were 18 sec and 19 sec, respectively. The low-power MOSFET gas sensor was found to be suitable for applications in portable gas monitoring units and automobiles.

• Periodical: Key Engineering Materials (Volume 543)
• Pages: 93-96
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.543.93
• Online since: March 2013
• Authors: Bum Joon Kim, Jung Sik Kim
• Keywords: Bulk Micromachining, Gas Sensor, Hydrogen, Low Power, MOSFET

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