Combined smart chemFET/resistive sensor array

Here we describe a novel CMOS compatible gas sensor array based on a combined resistive/chemFET sensor cell. We have fabricated an array of 70 sensors with integrated drive, gain and baseline removal circuitry using an AMS 0.6 /spl mu/m CMOS process. The sensing materials are carbon black/polymer composite (CB) thin films, which have been previously reported to have good vapour-sensing properties. Different CB films have been deposited onto the sensor array and have been shown to respond differently to volatile organic compounds. This combined sensing element both reduces silicon area and, more importantly, measures different physical properties of the same gas sensitive material improving discrimination and giving more insight into the sensing mechanism.