Gas sensors find increasing attention because of the large number of applications and the disadvantages of conventional solutions for the measurement of gases. Therefore many research teams develop oas sensors on the basis of MOSFETs. Besides the well-known MOSFETs with palladium gate electrodes for the detection of hydrogen, a number of other MOSFET-structures using dielectric layers are also developed. These MOSFETs, which are described in the literature, are classified in five types according to the position of the gate electrode to the sensitive layer. As an example a MOSFET gas sensor with gate electrodes parallel to the drain current and heteropolysiloxanes as the sensitive layer for SO2 is presented.
