Research On Monolithic Integration Of Two-dimensional Magnetic Field/pressure Sensor Based On MEMS Technology

In this paper,a two-dimensional?2D?magnetic field/pressure sensor is designed based on the technology of MEMS and isolation technology.The structure consists of two-dimensional magnetic field sensor and piezoresistive pressure sensor.The 2D magnetic field sensor uses silicon magnetic sensitive transistors as magnetic sensitive devices,and two magnetic sensitive units are formed along x axis and y axis,respectively,and first differential structure magnetic sensor unit is a differential structure consisting of magnetic transistor and load resistance placed along y axis,which can realize the measurement of x direction magnetic field component?B_x?.The second differential structure sensitive unit is a magnetic transistor placed along x axis direction and a load resistor,and can realize a y direction magnetic field component?By?measurement;in combination with the stress analysis and piezoresistive effect of the elastic element,four piezoresistors are designed on the surface of the square silicon membrane to form the Wheatstone structure,which can measure the pressure?P?perpendicular to the surface of the chip.On this basis,the simulation model of the 2D magnetic field sensor was constructed by using the analog semiconductor device electrical property software Silvaco TCAD Atlas,and the IC-VCE characteristics,magnetic sensitivity characteristics and temperature characteristics.The ANSYS Mechanical APDL finite element simulation software was used.The pressure sensor structure simulation model was constructed and the pressure sensitive characteristics were simulated and analyzed.The2D magnetic field/pressure sensor chip layout was designed by L-Edit software,and the process was fabricated and packaged.In room temperature environment,the I_C-V_CE characteristics,magnetic sensitive characteristics,pressure sensitive characteristics and temperature characteristics of 2D magnetic field/pressure sensor are studied by semiconductor parameter testing system,static calibration system of magnetic field sensor,automatic pressure transmitter testing system and high and low temperature test box.When the working voltage is 5.0 V and IB is 3.0 mA,the magnetic sensitivity of the sensor in x direction is 308.7 mV/T,in y direction is 181.0 mV/T,and under the pressure of 0.0 kPa¹00.0 kPa,the pressure sensitivity is 0.006 mV/kPa.The sensor can realize the measurement of xy plane magnetic field vector and external pressure.It lays a foundation for simultaneous measurement of two-dimensional magnetic field and pressure.