Fabrication and characterization of resonant aerosol particle mass sensors

This work presents thermally actuated MEMS resonators specifically designed for mass measurement of air-borne particles and experimental measurement of resonators' mass sensitivity. The resonators have resonant frequencies in the few hundreds of kHz to a few MHz and despite their relatively low frequencies exhibit high quality factors (Q) (a few thousands) under atmospheric pressure. The fabricated resonators were embedded in a custom made system comprised of a controlled aerosol particle generator, a particle director/accelerator and an alignment apparatus. Aerosol particles with known size and composition were generated and deposited on the resonators to determine their mass sensitivities. Mass sensitivities in the order of hundreds of Hz/ng have been measured for the resonators that are in good agreement with the theoretically calculated values.