Design, fabrication, and testing of MEMS-based miniaturized potentiometric nitric oxide sensors

We report on the development of miniaturized potentiometric nitric oxide (NO) sensors. This work covers the design, fabrication and testing of these NO sensors. In particular, microelectromechanical systems (MEMS) fabrication techniques were utilized to miniaturize the size of the sensors. Sensors were fabricated using both shadow mask and photoresist mask fabrication methods. Arrays of up to 15 sensors were electrically connected in series during the fabrication process to improve the signal of the overall device for a given NO concentration. Testing on these sensor arrays toward NO was carried out at 550 °C to compare the performance of the various designs of the sensor. Sensitivity below the ppm level was demonstrated with the photoresist-masked 15-sensor array. Long-term stability of the miniaturized sensor array when operating at high temperatures needs to be improved before practical applications of this MEMS sensor technology can be realized.