Structural Optimization On N-polar AlGaN/GaN Resonant Tunneling Device

Terahertz technology,which has received widespread attention for its application in the field of medicine,detection,communication,radar and so on,is an emerging science and technology.Resonant tunneling diode,a terahertz source,attracted many attention in the field of terahertz because of its characteristics of high frequency and high rate,However,The output power of resonant tunneling diode based on Ga As and Si is too low,can not meet the requirements of the output power of terahertz source.New materials are considered to improve the preformance of resonant tunneling diodes.At the same time,the advantages of Ga N materials gradually highlight,So Ga N materials develop far-reaching in the field of high power microwave devices.So the Ga N based resonant tunneling diode have been the focus of a large number of researchers.However,the application of Ga N based resonant tunneling diodes is also facing many difficulties,such as the defects and the polarization charge at the heterojunction interface will seriously affect the performance of the device.In this paper,the main research is focus on the modeling of resonant tunneling diode and the simulation of material parameters and device structure,and the results are as follows:1,The Ga N based material parameters and physical models using in simulation are given.N-polar Ga N material's advantages and challenges,compared with Ga-polar Ga N materials are analysised in this paper.2,N-polar and Ga-polar Al Ga N/Ga N resonant tunneling diode are modeled using the Silvaco software,based on the polarization effect of the Ga-polar and N-polar Al Ga N/Ga N heterojunction interface using Schrodinger Poisson equation and Non-Equilibrium Green's function approach.Through the analysis of I-V curve,conduction band diagram,the relationship between transmission coefficient and energy,the differences between N-polar and Ga-polar Al Ga N/Ga N resonant tunneling diode are researched.The influence of barrier width,well width,doping concentration,Al component and isolation layer thickness on the properties of N-polar Al Ga N/Ga N resonance tunneling diode are researched,and it is found that lower barrier width,higher doping concentration,lower isolation layer can improve the performance of the device,meanwhile well width and Al component should be compromised.Then the process steps of N-polar Al Ga N/Ga N resonant tunneling diode is given.3,The influence of the external bias on the transmission coefficient of the N-polar Al Ga N/Ga N resonant tunneling diode is studied in this paper.It is found that the peak value of the transmission coefficient of the N-polar Al Ga N/Ga N resonant tunneling diode under the peak voltage does not reach the maximum value.Based on the study of asymmetric N-polar Al Ga N/Ga N resonant tunneling diode,the peak value of the transmission coefficient is improved.Through the study of the relationship between transmission coefficient and energy at different bias voltage,with asymmetric barrier width,asymmetric doping concentration,asymmetric Al component,asymmetric isolation layer thickness,it is found that the RTD with narrow emission barrier,wide collection barrier have higher peak value of the transmission coefficient under peak voltage,while reducing the emitter and collector doping concentration,increasing the thickness of isolation layer can also increase the peak value of the transmission coefficient under peak voltage.