The Design Of High Temperature Pressure Sensor And Computr Simulation

Pressure sensor used for high temperature is regarded highly by people for its specialapplications. It is necessary for us to make a pressure measure in high temperature environmentsuch as the field of petroleum, chemical industry, aeronautics and astronautics . Polysilicon hightemperature pressure sensor and SOI high temperature pressure sensor are the ideal product forreplacing the ordinary diffusion silicon pressure sensor in the high temperature pr essure measureat present market.A polysilicon-AlN film pressure sensor used for high temperature is developed in this paper.It is designed by the characteristic of polysilicon high temperature pressure sensor, SOI hightemperature pressure sensor as wel l as MEMS technology. The essential is using AlN film toseparate piezo-resistors from silicon elastic film. The expansion coefficient of AlN is close tothat of silicon with a good stiffness and high break -down voltage as well as good chemical steady.It is benefit to thermal dissipation for bridge with its high thermal conductivity. That can solvethe problem of drift of offset with time when starting and powering sensors. The properties(electric and thermal drift for offset, non -linearity) of pressure sensors fabricated by thesesubstrates are particularly excellent. Piezo -resistors consist of nano-polycrystal silicon, which ismade from sputtering amorphous silicon by Al induced crystallization at temperature of 600℃.The silicon cup is prepared with anisotropyically etching the substrate and the resistance isprepared with plasma etching. Packaging of this device is also prepared by PbO -ZnO-B2O3process.It is easy to realize the integration because the process of polysilicon-AlN thin film pressuresensor is compiled with the traditional CMOS process. So it is an ideal high temperature pressuresensor with good performance.Also,the temperature distribution in the model was simulated essentially by using ANSYSsoftware, respectively comparing the temperature distribution among AlN, 2 SiO , 2 3 Al O as heatdispersion-layer, and the temperatures at resistor center for different thickness of these heatdispersion-layers .