| High sensitivity sensors play a key role in the development of artificial intelligence technology.Sensors are everywhere in the fields of smart home,driverless,machine vision,security monitoring,etc.The sensors market of China has also shown a higher growth rate in recent years.The Hall effect sensor which is a kind of magnetic field sensors,that converts a magnetic signal into an electrical signal,has been widely used in automotive electronics,industrial control systems,consumer electronics and medical applications.Traditional Hall sensors are made of materials such as silicon,indium arsenide,gallium arsenide,etc.,and are often used in environments below 150 °C.However,in some special areas,such as space detection,military and nuclear power plants,traditional Hall sensors will have various reliability problems in these high temperature and high radiation environments.GaN-based III-V materials are one of the important representatives of the wide bandgap semiconductors.This kind of material is potentially useful for high temperature Hall sensors because of its large bandgap,so it has a higher breakdown electric field and better high temperature operation stability.Secondly,the fabricated Hall sensor has low noise and high sensitivity due to the theoretical intrinsic carrier concentration of GaN is very low.In addition,the confinement of the two-dimensional electron gas(2-DEG)located close to the AlGaN/GaN interface,so the mobility of 2-DEG is significantly higher than the electron mobility of bulk materials.In a word,Hall sensors fabricated using such GaN-based heterojunction materials have high operational sensitivity and are well suited for use in high temperature operating environments.The main research contents of this paper include:(1)Based on the Sentaurus TCAD tool,some key physical models such as Polarization model,Low Field Mobility model and Galvanic Transport model suitable for GaN materials are adopted,besides,the polarization model and low field mobility model are built by Tcl scripting and C++ language respectively.(2)Combining theory and results of simulation of the GaN based 3D Hall plate,the effects of device aspect ratio and the length of sensing electrodes on the geometric parameters of the device are analyzed.The results show that the aspect ratio of the device is greater than 3 and the smaller the sense electrode,the Hall voltage of the device is closer to the ideal Hall voltage.(3)This paper proposes a design for the vertical Hall sensor based on the wide-bandgap AlGaN/GaN heterojunction material,which adopts a shallow etching of 2-DEG channel barrier to form a locally trenched structure.The material parameters and physical models of the proposed device are first calibrated against real device test data,and then the key structural parameters such as device electrode spacing ratio,mesa width and sensing electrode length are optimized by using technology computer aided design(TCAD)and the device characteristics are analyzed.(4)Based on the research of GaN based horizontal and vertical Hall sensors,this paper combines the design and simulation of GaN-based 3D Hall sensors.The output characteristics,temperature characteristics and angular characteristics of the three-dimensional Hall are studied.The results show that the designed three-dimensional Hall sensor can simultaneously detect the spatial three magnetic field components and has a better temperature stability.(5)In the experimental part,this paper designs a horizontal Hall sensor with cross-shaped and focuses on the effect of alignment on the offset voltage of the device,the effect of the device aspect ratio,the size of the sensing electrode and the temperature stability of the device will be discussed in detail. |
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