Design and fabrication of a MEMS-based gas sensor containing WO3 sensitive layer for detection of NO2

A gas sensor based on microelectromechanical systems (MEMS) technology containing a WO3 sensitive layer was designed, simulated, and fabricated. The gas sensor consists of a silicon substrate, a platinum microheater, gold interdigitated electrodes, and a WO3 sensitive layer. The active area with dimensions of 0.4 mm x 0.4 mm is located at the center of a sensor (3 mm x 3 mm). The experimental results show that the microheater provided heating for the WO3 sensitive layer at low power consumption and accurate temperature control. At a power consumption of only 40 mW, the temperature reached 319 degrees C at the center of the MEMS platform with uniform heating. In addition to that, the above mentioned gas sensor exhibited a high response to NO2 with optimized sensitivity recorded at the working temperature of 170 degrees C. With 10 ppb of NO2, the response of the sensor could reach up to 5.8 and the power consumption is 17.2 mW. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)