Study On The Irradiation Induced Damage Of AlGaN/GaN HEMT Devices

Compared with the previous two generations of semiconductor materials,the third-generation semiconductor Gallium nitride?GaN?materials have more excellent properties,such as wide band gap?3.39e V?,high electron mobility,high thermal conductivity,high breakdown electric field,high temperature and strong radiation resistance.GaN-based devices are highly competitive in high-frequency and high-power applications due to their strong breakdown electric field,high output power,and high temperature resistance.Among them,the high electron mobility transistor?HEMT?based on the GaN heterojunction material can generate an area density as high as?10¹³/cm² at the heterojunction interface without doping.GaN HEMT devices have the dual advantages of high carrier concentration and mobility,and can meet the requirements of microwave power devices with higher power,higher frequency and smaller volume.However,GaN HEMTs still face huge challenges in the complex space environment,despite their excellent radiation resistance.Therefore,it is an important scientific problem to study the radiation effects of GaN-based HEMT devices,to deeply explore the micro-characteristics of device defects caused by radiation and discover the radiation damage mechanism of GaN HEMT devices.Aiming at the reliability issues related to the irradiation of GaN-based HEMT devices,this paper has carried out reliability experiments related to the application of space irradiation.The main research results are as follows:?1?3-MeV proton irradiation experiments of AlGaN/GaN HEMT devices were carried out.The devices experienced degradation of electrical performance after 3-Me V proton irradiation.The main degradation mechanism is considered to be the increase of negatively charged trap density in the channel,which depletes more electrons and reduces the carrier mobility in the channel 2-dimensional electron gas?2-DEG?.In order to verify this view,we conducted a low frequency noise?LFN?test on the basis of theoretical analysis.The test results show that the defect density of the device increased significantly after 3-Me V proton irradiation.It is demonstrated that the negative trap charge generated by the device channel layer after 3-Me V proton irradiation is the main reason for the electrical performance of the device.?2?3-MeV proton irradiation experiments based on hydrogen-treated AlGaN/GaN HEMT devices were carried out.Compared with the non-hydrogenated AlGaN/GaN HEMT device,proton irradiation experiments based on hydrogenated devices have caused more serious degradation of the device.Low frequency noise tests were performed on AlGaN/GaN HEMT devices before and after the experiment.It was show that the proton irradiation experiment based on hydrogenated devices caused more radiation-induced defects in the device.?3?High-temperature annealing experiment after 3-Me V proton irradiation for hydrogenated and non-hydrogenated devices were performed.The experimental results show that the electrical performance of the proton irradiated device is improved,but the the magnitude of improvement of the devices irradiated after hydrogenated is worse than that of the non-hydrogenated irradiated device.It is demonstrated that the hydrogen defects have lower energy and better stability than defects produced after only proton irradiation,resulting in less defects changed at high temperature annealing.?4?Heavy ion irradiation experiments of Al GaN/GaN hetero-junction wafer were carried out.Using CAFM for the first time to characterize the latent tracks generated after heavy ion irradiation.The results showe that many high current points appeared on the surface of the sample after heavy ion irradiation.The generation rate of shallow tracks is 100%,the latent track size is 20-30 nm,and the latent track includes the track core and the track halo.The current distribution of the track core and track halo is consistent with the irradiation energy distribution.