Design and Fabrication of a Micro-Size Thermionic Ionization/Flame Ionization Detector for Gas Phase Chemical Analytes

A simple, MEMS base micro-chemical detector utilizing the principles of gas ionization, has been designed and fabricated. The device contains a polysilicon micro air-bridge heater structure with integrated polysilicon electrodes. The design of the devices allows it not only functions via thermionic emission, but also via chemi-ionization if a proper Pt catalyst is applied and it is operated in an environment containing hydrogen. When properly biased the device has been shown to heat to high temperatures where thermionic emission can begin to occur. Hydrocarbon chemicals in the gas phase have shown to ionize, via thermionic ionization and have been collected, producing a measurable current signal