A GasFET concept for high temperature operation

A new concept for high temperature gas detection with a floating gate field effect transistor (FG-FET) will be presented. The function of the FG-FET is based on measuring work function changes due to an adsorption and desorption process of gas molecules on a sensing film. All existing concepts are working in a temperature range from room temperature up to 200 °C. Higher temperature leads to significant leakage current in the transducer electronics and consequently to device breakdown. The new concept has two key benefits. Firstly, a full isolation achieved by using SOI-substrates and secondly a vertical MOSFET with high doping concentrations in the channel region. Both improvements lead to an extension of the temperature range up to 350 °C. This increases the range of layers for chemical sensitive gasdetection and allows the operation in hot ambiance.