Study On SOS High-temperature Pressure Sensor

The SOS high temperature pressure sensor studied in this subject is a piezoresistive pressure sensor based on SOS(Silicon on Sapphire)device technology.In the aerospace field,pressure sensors often need to work in hightemperature environments for a long time,while traditional diffused silicon pressure sensors cannot withstand high-temperature environments above 120°C due to the PN junction leakage current problem.The paper introduces a SOS high temperature pressure sensor that can work for a long time under high temperature conditions above 150?.This type of sensor covers the measurement needs of multiple pressure ranges,with high sensitivity and stable performance,and can be widely used in the measurement of pressure signals in the aerospace and other defense fields.This thesis first introduces the research status and technical characteristics of SOS pressure sensors.By comparing and analyzing the SOS pressure sensor and the traditional diffused silicon pressure sensor,the performance advantages and realization methods of the SOS pressure sensor are explained.Subsequently,the basic working principle of the piezoresistive pressure sensor is introduced from the two aspects of the piezoresistive effect of silicon and the measurement principle of the DC bridge.Secondly,the paper focuses on the design process of SOS pressure sensor.On the one hand,it is the design content of SOS sensitive components,which mainly includes analysis and parameter design of metal elastic diaphragm,sensitive chip layout,packaging structure,process flow,etc.Aiming at the most important metal elastic diaphragm design,theoretical calculations combined with software simulation and analysis are also used to make full use of the stress distribution on the surface of the diaphragm,so that the sensitive components obtain higher sensitivity.On the other hand,through the overall design,the circuit part of the sensor realizes the functions of temperature compensation,constant current source power supply,differential amplification,debugging,etc.,and adjusts the weak voltage signal output by the sensitive element into a standard signal that meets user requirements.Finally,according to the design plan in the paper,samples of SOS pressure sensor with three typical ranges of 0.6MPa,10 MPa and 40 MPa were tried.According to the characteristics of the SOS pressure sensor and the actual measurement needs of users,a suitable detection plan was developed and a corresponding detection system was built.Detect the accuracy of each sensor sample and calculate,organize,and analyze the test data to confirm that the high temperature resistance and accuracy indicators of the SOS pressure sensor can meet the user's index requirements,and the expected goal of this topic is achieved.