A Thermal Airflow Sensor Based on Mn-Co-Ni-O Thin Film

A thermoresistive calorimetric airflow sensor with high sensitivity based on Mn-Co-Ni-O (MCN) thin film prepared by magnetron sputtering is reported. The microbridge structure of MCN thin film with a size of 900μm × 20μm is fabricated by using bulk micromachining technology. The temperature coefficient of resistance (TCR) of the MCN thin film is approximately -34871 ppm/K at 293K and -21060 ppm/K at 373K. The fabricated sensor achieves an ultra-high sensitivity of 28.115 mV/(m/s)/mW with respect to input heating power and amplification factor, which is 10-fold better than the sensor with platinum (Pt) thin film. The proposed sensor demonstrates that the MCN thin film has promising applications in high-sensitivity thermal flow sensors.