Fabrication and application of polymer coated cantilevers as gas sensors

We have fabricated SiN"x cantilevers which can be used for applications as miniaturized gas sensors. Cantilevers were coated with polydimethylsiloxane as a chemically sensitive layer and the additional mass loading by the absorption of gas molecules was detected by measuring the change of the resonance frequency of the structures. For the detection of n-octane a sensitivity of -0.099 Hz/ppm is obtained. This value is comparable to the sensitivity of conventional quartz crystal microbalances. The simultaneous detection of the resonance frequencies of different cantilevers for analyzing a gas mixture is demonstrated.