Research Of MEMS Infrared Gas Sensor

Gas sensors have broad application prospects in many fields like atmosphericpollution detection, flammable, explosive, toxic and harmful gas detection, diseasediagnosis, as well as military aplication. Because of the disadvantages of traditional gassensors like bulky, high power consumption and short life, it has a practical significance todevelop a new type of gas sensor which has small size, low power consumption, andlong life and is easy to make integration and mass production..This thesis focuses on a MEMS-based infrared gas sensor structure to achieveminiaturization, mass production, and a high level of integration. Concept of integratedMEMS chips with thermal emitter and bolometer elements are given and the chips aresucessfully fabricated. The main contents of this thesis include:(1) Based on f finite element analysis software COMSOL Multiphysics, Pormance oftwo core units of the integrated MEMS infrared gas sensors were simulated. Theemission unit was simulated with joule heat and thermal expansion module and itsstructural parameters were optimized by using parameters scanning. The detection unitwas simulated with RF module.. The regularity of the unit and IR absorption rate wasanalyzed.(2) Based on existing experimental conditions and proposed device structure, wedesignd a set of device fabrication process. Key processes such as SiNx etch and Si deepetching were tested and the fabrication parameters were optimized.(3) According to the designed process, we have produced some samples of MEMSinfrared gas sensor. Then we tested some performance of the samples, and raised someimprovement suggestions based on the current test results.