A Novel Thermal Acoustic Particle Velocity Sensor with High Sensitivity and Low Power Consumption

This paper presents a novel thermal acoustic particle velocity sensor based on Mn-Co-Ni-O (MCN) thin film, designed to efficiently detect subtle acoustic signals with reduced power consumption. A dry etching-based fabrication process is proposed to address the incompatibility of the MCN thin film with wet etching, achieving a fully suspended wire structure that eliminates boundary layer effects induced by the silicon substrate. Additionally, a theoretical model linking applied power to sensitivity is proposed to optimize the sensor's operating point. As a result, the sensor achieves a 36-fold improvement in sensitivity under the same power consumption compared to the sensor based on platinum (Pt) thin film, reaching 156.6 mV/(m/s)/mW at 1 kHz.