Research On Space Magnetic Vector Sensor With Low Cross Interference Based On MEMS Technology

In order to realize the accuracy of the spatial magnetic vector sensor to detect the spatial magnetic field,it is necessary to reduce the magnetic cross interference in three directions.A low cross-interference spatial magnetic vector sensor based on MEMS technology and isolating technology was designed in this paper,using the silicon wafer as the substrate,four solid-structure silicon magnetic sensitive transistors?SMST1,SMST2,SMST3,and SMST4?and two Hall magnetic field sensors?HM1 and HM2?were fabricated on the device layer.Using SMST1,SMST3 and two load resistors to form the first pair of differential structures as the first magnetic sensitive unit,the x-direction magnetic field component?B_x?detection can be realized;using SMST2,SMST4 and two load resistors to form the second pair of differential structures as the second magnetic sensitive unit,the y-direction magnetic field component?By?detection can be realized;the HM1 and HM2 Hall output terminals are serially outputted as the third magnetic sensitive unit,which can realize the z-direction magnetic field component?B_z?detection.Based on the basic structure of the sensor,the low-interference spatial magnetic vector sensor structural model is constructed by using semiconductor device simulation software?TCAD-Atlas?,and the magnetic sensitivity,magnetic cross-sensitivity and temperature characteristics of the model structure are simulated.According to the simulation results,the process of the sensor chip is established,and the layouts of the sensor chip is designed and drawn by using L-Edit software.The low cross-interference spatial magnetic vector sensor chip is fabricated by using the MEMS process.And the chip is non-magnetized package.In this paper,at room temperature,using the self-built sensor characteristic test systems,the I_c-V_ce characteristics of SMSTs,magnetic sensitivity characteristics,magnetic cross-sensitivity characteristics and temperature characteristics of three-direction magnetic field sensors were tested and analyzed,respectively.The experimental results show that when-300.0 mT?B?300.0 mT,the supply power is 5.0 V and the base injecting current is 3.0 mA,the three-direction magnetic sensitivities of the sensor can reach 229.9 mV/T,207.4 mV/T and 197.2 mV/T,respectively,and the cross-interference of the three-direction sensors is lower than 6.3%.The spatical magnetic vector sensor uses a wall to effectively reduce magnetic sensitivity cross-interference in three directions.