Design And Fabrication Of Silicon Carbide Fiber Fabry-Perot High Temperature Pressure Sensor

As one of the most common sensors in industrial practice,pressure sensor plays a key role in many fields of military and civil use.Due to many limitations of the traditional normal temperature pressure sensor,such as the device material and packaging structure,it is impossible to complete the in-situ measurement of pressure parameters in the ultra-high temperature and harsh environment.Therefore,the research on the high-temperature pressure sensor has gradually become a hot spot.Pressure sensor is mainly compressive resistance,capacitance and fiber type and other types,compared with other types of pressure sensors,optical fiber type pressure sensor has a resistance to electromagnetic interference,low cost,environment of high temperature stability is good wait for an advantage,at the same time,silicon carbide material with high melting point,good thermal stability,good optical properties and resistance to chemical corrosion,etc,become the ideal material of high temperature pressure sensor.In this paper,based on silicon carbide material,a fiber optic Fabry-Perot pressure sensor suitable for high temperature environment is designed.In this paper,starting from the urgent demand for in-situ measurement of pressure parameters in high temperature and harsh environment,the silicon carbide fiber Fabry-Perot high temperature pressure sensor was deeply studied.The main research contents are divided into the following three parts:(1)Sensor designThe whole structure of the sensor is designed mainly based on the principle of Fapo-Perot interference,and the specific parameters of the sensor sensitive structure are designed according to the theory of thin plate and the limitation of Faisel demodulation system.Finally,the static mechanics simulation is carried out with COMSOL software to verify the feasibility of the sensor size design.(2)sensor preparationBased on the existing MEMS processing technology and design requirements,a complete process preparation process was designed,the sensor was prepared according to the process,and the etching process,thinning and polishing process,laser process and bonding process in the preparation process were studied and analyzed in detail and specific optimization.(3)Sensor packaging and testingThe fiber integration technology based on silicon carbide fiber sensor was explored,and finally the mechanical encapsulation structure of silicon carbide ceramic was adopted.The gas tightness and bonding strength of the prepared sensor were tested first.The gas tightness test result was 1.5×10-9Pa·m~3/s,and the bonding strength could reach 23.7 MPa,which could meet the basic manufacturing requirements of MEMS devices.Finally,a normal temperature test system and a temperature/pressure composite test system were built to test the pressure sensitivity of the sensor.The test results show that the sensitivity of the sensor at normal temperature is 0.929nm/k Pa,and the nonlinear error is less than 0.35%fs.At a high temperature of 600?,the sensor prototype has a sensitivity of 0.952nm/k Pa and a nonlinear error of less than 0.41%fs within the range of test pressure.