Integrated silicon-based chemical microsystem for portable sensing applications

This paper presents a chemical microsystem based on the integration of a silicon-based resonant microsensor and a CMOS ASIC for portable sensing applications in air. Cantilever-based microresonators coated with chemically-sensitive polymer films are used as microsensors. The CMOS ASIC utilizes the self-oscillation method, which uses an amplifying feedback loop. For improved short- and long-term frequency stabilities, the ASIC also includes several control circuits such as an automatic gain control loop, an automatic phase control loop, and a frequency drift compensation loop. The performance of the implemented microsystem has been evaluated experimentally by detecting various volatile organic compounds.