CMOS single-chip multisensor gas detection system

We present a novel single-chip smart chemical microsensor system fabricated using industrial CMOS technology and post-CMOS micro machining. It combines three different rnicromachined transducers (mass-sensitive, capacitive, and calorimetric) all of which rely on polymeric coatings as sensitive layers to detect airborne volatile organic compounds (VOC). A temperature sensor is included to account for the strong temperature dependence of volatile absorption in polymers. Integration of microelectronics and micromechanical components on the same chip allows for controlling of the sensor functions, and enables on-chip signal conditioning that drastically improves the sensor performance. The circuitry includes biasing, amplification, and a serial interface to transmit data to off-chip recording units. The chip forms an integral part of a handheld chemical sensor unit to discriminate and quantify VOC's.