Micromachined Mass-Sensitive and Capacitive Chemical Multisensor Using Single Polymeric Sensing Film

We present a novel micromachined chemical multisensor that simultaneously detects mass and dielectric property changes in the same polymeric sensing film. The multisensor is comprised of a cantilever-type, mass-sensitive resonant sensor with a semicircular annulus and an embedded on-resonator interdigitated electrode structure for capacitive sensing. The resonant chemical sensor utilizes a high-Q in-plane resonance mode enabling sub-parts per million limits of detection for volatile organic compounds. The embedded capacitive sensor enables the discrimination between toluene and methanol by evaluating the ratio between the mass-sensitive and capacitive sensor signal.