Design Of A Novel MEMS Piezoresistive Pressure Sensor

MEMS piezoresistive pressure sensor has a wide range of applications in aerospace,automotive electronics and other fields because of its small size and high linearity.With the increasing demand of MEMS piezoresistive pressure sensor with high sensitivity and low nonlinearity in aerospace and other fields,it is necessary to develop a new type of pressure sensor with high performance.Therefore,a new type of pressure membrane structure is proposed to realize the high sensitivity and low nonlinearity of MEMS pressure sensor.In this paper,the MEMS pressure membrane is taken as the research object,the small deflection deformation is used to ensure the linearity of the new MEMS pressure membrane,and the Wheatstone bridge is used as the testing method.The research process of this paper is as follows: firstly,the research status of the subject is investigated.Through the analysis of the research status of MEMS piezoresistive pressure sensor at home and abroad,the pressure membrane structure and structural characteristics of the existing MEMS piezoresistive pressure sensor are summarized,and the working principle of the sensor based on piezoresistive effect and the related theory of pressure membrane structure design are introduced.Secondly,the structure of a new type of pressure membrane is designed.The sensitivity of the sensor is improved by designing a short narrow beam structure on the pressure membrane to form a high stress concentration area and changing the square pressure membrane into an elliptical arc petal pressure diaphragm.The non-linearity of the sensor is reduced by designing a square island structure at the upper edge of the compression surface of the pressure film and a cross beam structure on the back of the pressure membrane.The mechanical properties of the new pressure membrane under full range pressure are simulated and analyzed,and the influence of each part of the structure on the new pressure membrane on the mechanical properties of the film is studied,and then the size of the new pressure film structure is optimized.An approximate mathematical relationship between the geometric size variables of the new pressure membrane structure and its mechanical properties is established,on the basis of which the optimization model of the new pressure membrane structure is constructed,and the size of the new pressure membrane structure is optimized according to the constraint conditions.finally,the performance of the new pressure membrane structure is simulated and analyzed.Through the simulation of the performance of the new pressure membrane,the output voltage?sensitivity and Nonlinearity of the corresponding sensor are calculated.The effects of the membrane width and thickness of the new pressure membrane structure on the output voltage and sensitivity are analyzed.The main work of this paper is to design a new type of MEMS pressure membrane structure.Compared with other membrane structures,the new MEMS membrane structure proposed in this paper has the maximum membrane stress to achieve high sensitivity and low membrane maximum deformation to ensure high linearity.