The Optimization Of Structure For AlGaN/GaN HEMT And The Simulation Of Electrical Property

GaN,as the third semiconductor material,has the advantages of high electron drift velocity,wide band gap and high breakdown voltage,and can work in high frequency,high power,high temperature and corrosive environment.Under the combined action of spontaneous polarization and piezoelectric polarization,the high density AlGaN/GaN(2DEG:Two dimensional Electron)can be formed at the interface of the heterojunction.These outstanding features make AlGaN/GaN HEMT(HEMT: High Mobility Transitor)in wireless communications,automotive and aerospace electronics,power transmission and power electronics devices have a unique advantage.In the application of microwave,the larger output power and higher working frequency are the main research directions.In the field of power electronics applications,the breakdown voltage of the device is the key to determine its market competitiveness.This paper is based on this purpose,to carry out the work of optimizing device structure in two aspects of optimization design and simulation of device barrier layer to improve the DC characteristics and frequency characteristics of microwave HEMT.On the other hand,the buffer layer device optimized design and simulation,improve the power switch HEMT off the characteristics,inhibit the spillover effect on state current.The effects of the doping of the barrier layer on the I-V characteristics,transfer characteristics and frequency characteristics of the device were studied using Silvaco ATLAS simulation software.Considering the polarization effect model and the mobility model(fldmob model),the Netwon method is used to calculate the DC and AC characteristics.The I-V characteristics of the device when the gate voltage is 1,0,-1,-2V,the transfer characteristics of the device when the drain voltage is 1V and the frequency characteristic of the 1-100 GHz is obtained.The results show that the DC and frequency characteristics of the device can be improved by doping the barrier layer.The DC characteristics of AlGaN/GaN HEMT devices with AlN interlayer were simulated,and the effect of AlN thickness on the device performance was discussed.The DC and AC characteristics are analyzed in detail.The results show that the insertion of AlN spacer layer improves the band discontinuity of the AlGaN/GaN interface,alloy scattering effects on channel electron mobility decreases,inhibition in the 2DEG channel spillover,improved electron mobility and electron concentration.When the AlN layer thickness reaches 2nm,the quantum well depth increases 1.2 times,the electron concentration increases by a factor of,and the leakage current is increased by 23%.The migration rate is affected by the roughness scattering and the scattering of alloy.When the thickness of AlN layer is 0.2nm,the migration rate is the largest.They can Slightly improved frequency characteristics.The band distribution,I-V characteristics and transfer characteristics of P doped AlGaN layer and GaN layer with GaN buffer layer were studied.This paper focuses on the analysis of the switching power of the device in the power electronic devices with high leakage voltage,which can effectively reduce the threshold voltage of the device through the A structure and the B structure.