Gas chemical sensitivity of a CMOS MEMS cantilever functionalized via evaporation driven assembly

This work demonstrates an electrostatically actuated resonant microcantilever fabricated in a complementary metal oxide semiconductor process and functionalized with a chemically sorbent polymer layer for the detection of volatile organic compounds. Deposition of the chemically sorbent layer is controlled through evaporation-driven assembly. Analytical and finite element analysis models of the deposited polymer layer on the microcantilever resonant frequency and mass sensitivity are presented. Fabrication of the chemical sensor, including a description of polymer deposition through evaporation-driven assembly within a capillary, is detailed. The completely functionalized resonator demonstrates a limit of detection of 1.6 ppm for toluene. An optimal polymer sensitive layer deposition of 42% of the total beam length is measured from frequency instability and sensitivity tests. (paper)