Design And Characteristic Research Of Magnetic Field Sensor Based On Dual-Drain Field Effect Transistor

There are many types of magnetic sensors.Researchers have been pursuing magnetic sensors with superior performance.Among them,sensors with high performance,miniaturization,low power consumption,and low cost development potential are attracting more attention.According to different operating principles,magnetic field sensors can be divided into Hall effect-based magnetic field sensors and magnetoresistive effect-based magnetic field sensors.This dissertation focuses on field-effect transistor-based magnetic field sensors and proposes a new type of magnetic field sensor-Al GaN/GaN heterojunction based vertical structure CAVET-like magnetic field sensor.By using Silvaco TCAD simulation software,the relevant electrical characteristics of the Si MOSFET magnetic field sensor,the GaN HEMT magnetic field sensor,and the CAVET-like magnetic field sensor are studied respectively.The main conclusions are as follows:For the dual-drain Si MOSFET magnetic field sensor and the GaN HEMT magnetic field sensor,its electrical characteristics are the same as those of a traditional FET in the absence of magnetic field,and the current difference of the split dual-drain is zero.When a magnetic field is applied,the current difference of the split dual-drain changes due to Lorentz force.The research results show that changing the gate voltage,drain voltage and drain spacing can adjust the relative sensitivity of the device to a certain extent,but the relative sensitivity values are all low.For the CAVET-like magnetic field sensor based on the Al GaN/GaN heterojunction vertical structure,the research results show that when the gate voltage is constant,that is,when the channel2DEG concentration is constant,the drain current difference becomes larger and the relative sensitivity also gradually increases with the increasing of magnetic induction intensity.When the magnetic induction intensity increases to 0.05 T,the relative sensitivity of the device is as high as487.92%/T(V_D=10 V,V_G=-3 V).As the gate voltage increases,the channel 2DEG concentration increases and the current difference of the split drain increases,but its relative sensitivity decreases.The drain current difference gradually decreases as the drain voltage increases and the relative sensitivity is also reduced.The drain current difference increases as the current aperture length increases when the gate voltage is small.The difference of the drain current is reduced as the current aperture length increases when the gate voltage is large(greater than about-1 V).With the increase of Al composition,the drain current difference increases significantly due to the increase of polarization-induced 2DEG concentration and its relative sensitivity also increases.At the same time,its relative sensitivity decreases significantly as the temperature increases.This dissertation lays a foundation for improving the relative sensitivity of FET magnetic field sensors,designing new magnetic field sensors and the realization of new sensor devices.