CO Detection Investigation at High Temperature by SiC MISFET Metal/Oxide Gas Sensors^†

In order to investigate the necessary device improvements for high-temperature CO sensing with SiC metal insulator semiconductor field effect transistor (MISFET)-based chemical gas sensors, devices employing, as the gas-sensitive gate contact, a film of co-deposited Pt/Al₂O₃ instead of the commonly used catalytic metal-based contacts were fabricated and characterized for CO detection at elevated temperatures and different CO and O₂ levels. It can be concluded that the sensing mechanism at elevated temperatures correlates with oxygen removal from the sensor surface rather than the surface CO coverage as observed at lower temperatures. The long-term stability performance was also shown to be improved compared to that of previously studied devices.