| Pressure sensors have lots of application fields. Polysilicon pressure sensor's research and development widely promote its application.The thesis consists of Four parts. Part One (introduction to Chapter 1)gives an overall review on the research and development in the related fields. the research status on several kinds of high-temperature pressure sensors is introduced in the thesis. The principle and design of the polysilicon pressure sensor is discussed in detail in the thesis. Part Two (Chapter 2) focuses on the study of Polysilicon Nano-film MEMS Pressure Sensor structure . Part Three focuses on the layout of Polysilicon Nano-film MEMS Pressure Sensor structure. Part Four (conclusion)discuss the result of measurement of sensors.In part Two, firstly, the principles of polysilicon pressure sensors are discussed. Analysis was made what the affect to the sensitivity of sensors with the piezoresistive effect of Polysilicon Nano-film and the stress of mechanical structures of sensing diaphragms. For improve the sensitivity of sensors, sacrifice layer structure is used of the design of Polysilicon Nano-film MEMS Pressure Sensor structure. Polysilicon Nano-film MEMS Pressure Sensor structure 's temperature stability is greatly improved by depositing a poly-silicon film on the layer of SiO2, which has excellent insulation property between piezo-resistors and Polysilicon film. Compared with doped mono-crystalline silicon pressure sensor, Polysilicon Nano-film MEMS Pressure Sensor structure sensor shows great advantages in 200℃operating temperature. Secondly theprocedure of parameters design are described detailly. Based on,the photosensitive masks of MEMS Pressure Sensor structure chip are designed.The devices are simulated by Finite- element software,the sensitivity of the sensors is measured to be 50mV/0.2Mpa under a driving of 5 V dc,the linearity best then 0. 1%FS The overload capability over 5 times. The results proved the design project is advanced. |
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