Research On Key Technologies In Micro Structure Gas Sensor Design

MEMS technology has developed rapidly since the end of 1980s. Owning to their advantages of small size, lower power consumption, better sensitivity, better repetition and lower cost, mciro sensors on the basis of MEMS play an important role in gas sensor industry. Electronic nose manufactured by MEMS is an instrument, which comprises an array of chemical sensors with partial specificity and an appropriate pattern-recognition system, capable of recognizing simple or complex odors. Due to the advantages in the aspects of power consumption, size and selectivity, micro gas sensor and electronic nose find promising applications in food industry, aviation and spaceflight, environment inspection; thus this research area is of great importance and become an international research focus.In this dissertation, according to the subprogram"Foundation and measure techmology of Micro-Chemo-Mechanical System"of Jiangsu province nature science foundation program(BK2004214)"Research on core technologies of Micro-Chemo-Mec- hanical System", the key technologies of the micro structure gas sensor are discussed. The main works are as following:1. The state-of-the-art of the micro structure gas sensor and electronic nose which are manufactured by MEMS are presented first. The structure and principle of the gas sensor and electronic nose are also introduced.2. On the basis of the electrical conduction principle of the gas sensing film and the theory of finite element method of heat transfer, a closed membrane type gas sensor with micro hot-plate was designed. Finite element analysis of the designed sensor was implemented by ANSYS. The temperature distribution on the sensing film as a function of the thermal conduction, the relations between the power consumption of micro hot-plate and the length of the membrane and the affection of using Si-island to improve homogeneity of the temperature distribution on the sensing area were researched. Finally the structure of the sensor was optimized.3. The typical processes of MEMS are introduced. Finite element analysis of three kinds of sensors with different processes was implemented. The affection of the different processes on the power consumption of sensors was analyzed. Finally the process flow of the designed sensor was proposed.4. The structure and principle of the micro sensor array are introduced, as well as mathematic model of the micro sensor array is discussed. The thermal effect between...