Fabrication and characterization of a semiconductor MOSFET gas sensor
A novel MOSFET gas sensor for the investigation has been developed.
Its configuration resembles a "normally on" n-type thin-film transistor
(TFT) with a gas sensitive metal oxide as a channel. The device used in the
experiments only differs from common TFTs in the gate configuration. In
order to allow gas reactions with the SnO2-surface, the gate is buried under
the semiconducting layer. Without any gate voltage, the device works as a
conventional metal oxide gas sensor. Applied gate voltages affect the channel
carrier concentration and surface potential of the metal oxide, thus causing
a change in sensitivity. The results of the gas measurements are in accordance
with the electric adsorption effect, which was postulated by Fedor Wolkenstein
1957, and arises the possibility to operate a semiconductor gas sensor at
relatively low temperatures and, thereby, be able to integrate CMOS electronics
for processing of measurements at the same chip.
Senast uppdaterad: 2019-03-29