Study On Pressure Sensor With Metal-Silicon Hybrid Structure And Its Measurement System

With the improvement of the manufacturing technology of Micro Electro Mechanical System(MEMS),the application of MEMS piezoresistive pressure sensors is becoming widely used,which imposes higher requirements on performance.At present,the traditional piezoresistive pressure sensors have the problems of large temperature drift coefficient and low sensitivity.A pressure sensor based on silicon-aluminum(Si-Al)hybrid structure provides a solution for the above problems.As a result,this paper designed a pressure sensor chip and measurement system based on the silicon-aluminum hybrid structure.Firstly,a pressure sensor,composed of four Si-Al hybrid structures which are the mixed structure of doped silicon and metal aluminum,is proposed.The working principle of the pressure sensor is described,and then the structural and material properties parameters are theoretically deduced and simulated,while the theoretical sensitivity and signal-to-noise ratio are emphatically discussed.Subsequently,according to the theoretical derivation and simulation results,the layout of the Si-Al hybrid structure pressure sensor is designed,and the manufacturing process is accordingly determined,based on which,the processing and packaging of the sensor are completed.Secondly,a hardware measurement system is designed for the manufactured Si-Al hybrid structure pressure sensor chip.The system chooses the STM32F407ZGT6 microprocessor as the core,which can perform the functions of data acquisition and analysis,as well as thermostatic control based on PID.The software is based on μCOS-Ⅲ operating system and STemWin graphics editing,which can achieve real-time dynamic display of data,human-computer interaction graphical interface,and can realize wireless data transmission through Bluetooth,WIFI.Lastly,the experimental test and analysis,as well as the compensation of hardware and software for the packaged Si-AI hybrid structure pressure sensor were carried out.Experiment and comparisons show that,in the temperature range of-20°C to 50°C,the sensitivity of the pressure sensor can reach to 0.128 mV/(V kPa)and comprehensive accuracy can reach to 0.93%FS in the pressure range of 0～1000kPa,after being compensated by wavelet neural network and least square algorithm software.In the temperature range of-20°C to 60°C,the sensitivity of the pressure sensor can reach to 0.122 mV/(V kPa)and comprehensive accuracy can reach to 0.93%FS within the pressure range of 0 to 300 kPa,under hardware compensation and constant temperature control.If the above two sensing units are working together,double the sensitivity will be obtained which shows that the Si-Al hybrid structure pressure sensor and its measurement system have a high sensitivity and measurement accuracy.The involved research results can supply a useful reference for subsequent research on Si-Al hybrid structure pressure sensor.