High-temperature SiC MOSFET gas sensors

Due to tightening restrictions on combustion exhaust emissions, low-cost sensors are desired for monitoring NOx production in high-temperature exhaust streams. This paper reports the characterization of Silicon Carbide MOSFET NO sensors for use in combustion exhaust monitoring. SiC depletion-mode MOSFETs were fabricated using a thermally-grown silicon dioxide gate dielectric and a Pt catalytic metal gate electrode. SiC MOSFET gas sensors were characterized at temperatures as high as 525 degrees C in an ambient of synthetic air and NO (50-200 ppm) for 30 hours with no degradation.