Resonant-gravimetric particle sensors with air-filtering cantilever fabricated in low-cost non-SOI silicon

Abstract

This paper reports a novel resonant-gravimetric micro-cantilever for detecting air particles (e.g. PM2.5), which is single-sided fabricated in low-cost non-SOI wafers. To filter the particle with desired size, a row of barrier bars is integrated in an air-flow micro-channel which is embedded in the cantilever. After air flow with particles is pumped into the channel, the particles with concerned diameter can be trapped by the barrier bars at the cantilever free-end. Due to the high mass sensitivity, the blocked particles with slight mass can result in a detectable resonant frequency shift. To recover the sensor, the direction of the air flow can be reversed to blow off the trapped particles. By tuning the mesh-density of the barrier bars, the diameter of trapped particles can be customizable, which promises a great potential of this technique in different air pollution analysis and monitoring applications.