The Effect Of Neutron Induced Displacement Damage In Unbiased GaN HEMT Devices

GaN material has the advantages of wide bandgap,high breakdown electric field and high thermal conductivity,and has a broad application prospect in the aerospace field.However there are many kinds of ray and particles in the space environment.Although GaN material has wide bandgap and good anti-radiation performance,the radiation resistance performance of GaNbased devices is affected by the influence of intrinsic and non-intrinsic defects of GaN-based materials.As the current technologies develops and the new characterization methods appears,the anti-radiation performance of GaN HEMT devices has attracted more and more attention.In this context,this paper lucubrate and analysis on the neutron cause displacement damage resistance of GaN-based HEMT devices.The main research contents and results of this paper are as follows:(1)Using Monte Carlo simulation tool for experimental device modeling,Using Monte Carlo method simulation displacement damage after neutron incident device,and the different unit's non-ionizing energy loss and vacancy number is obtained according to the results of the simulation,it provides some reference for the following neutron irradiation experiments.simulation results show that after neutron irradiation device,in AlGaN layer produced more non-ionizing energy loss and have many defects.(2)The neutron irradiation experiment was carried out for AlGaN/GaN HEMT devices.By comparing the electrical characteristics before and after irradiation,it was found that the displacement damage caused by neutron irradiation will lead to the degradation of the electrical performance of the device.The analysis believed that it was due to neutron irradiation generated new defects near the channel.In order to further confirm the generation of defects and the effect of defects on devices,this paper uses a new characterization method: 1/fnoise,using 1/fnoise to accurately obtain the location of the main defect,and calculate the change of the defect concentration in the device before and after irradiation,and it was found that the defect concentration in the device increased after irradiation.According to these experimental results,it is found that the new defects introduced by neutron irradiation are mainly at the AlGaN/GaN heterojunction,which is consistent with the results of the Monte Carlo calculation.At the same time,this paper conducted a neutron irradiation experiment for AlGaN/GaN heterojunction.Using C-V test,the change of carrier concentration before and after irradiation was calculated.After analysis,it was found that body defects caused by neutron irradiation were mainly located in AlGaN Layer,these defects will trap the electrons in the channel,so that the concentration and mobility of the 2DEG is reduced,affecting the electrical performance of the device.(3)The neutron irradiation experiment was carried out for MOS GaN HEMT devices,and the changes of the displacement damage sensitive parameters of the device were obtained.Experimental results show that low fluence neutron irradiation can improve the electrical performance of the device,the analysis believes that the defects caused by neutron irradiation and the intrinsic defects of the material have recombined,but when high fluence neutron irradiation,the new defects will form the recombination center and scattering center,and affect the concentration and mobility of the two-dimensional electron gas in the channel,eventually lead to the degradation of the electrical performance.At the same time,the experiment also found that the gate of the device was not greatly affected after neutron irradiation.Compared with the AlGaN/GaN HEMT device in contact with Schottky,the ability of the gate of the MOS GaN HEMT device to resist the displacement damage effect better.