中子辐射导致的SiC功率器件漏电增加特性研究  

Study on characteristics of neutron-induced leakage current increase for SiC power devices

作　　者：彭超 雷志锋[1] 张战刚[1] 何玉娟[1] 马腾 蔡宗棋 陈义强[1] Peng Chao;Lei Zhi-Feng;Zhang Zhan-Gang;He Yu-Juan;Ma Teng;Cai Zong-Qi;Chen Yi-Qiang(Science and Technology on Reliability Physics and Application of Electronic Component Laboratory,the Fifth Electronics Research Institute of the Ministry of Industry and Information Technology,Guangzhou 511370,China)

机构地区：[1]工业和信息化部电子第五研究所,电子元器件可靠性物理及其应用技术重点实验室,广州511370

出　　处：《物理学报》2023年第18期329-337,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12075065,62274043);广东省基础与应用基础研究基金(批准号:2021B1515120043);广东省重点研发计划(批准号:2022B0701180002);广州市科技计划(批准号:202201010868)资助的课题。

摘　　要：基于14 MeV中子辐照研究了碳化硅(silicon carbide,SiC)肖特基势垒二极管(Schottky barrier diode,SBD)和金属氧化物半导体场效应晶体管(metal oxide semiconductor field effect transistor,MOSFET)器件的位移损伤退化特性.结果表明:总注量为1.18×10^(11)cm^(-2)的中子辐照不会引起SBD正向I-V特性的明显退化,但会导致反向漏电流出现显著增大.通过深能级瞬态谱测试发现中子辐照在SiC中引入的缺陷簇形成了能级位置E_(C)—1.034 eV处的缺陷.该深能级缺陷可能导致SiC漂移层费米能级向禁带中央移动,引起了肖特基势垒的降低,最终导致反向漏电流的增大.此外,中子辐照也会导致SiC MOSFET栅漏电增大.对应栅电压V_(gs)=15 V时,辐照后器件栅电流比辐照前增大了近3.3倍.中子辐照在氧化层中引入的施主型缺陷导致辐照前后MOSFET器件的栅氧导电机制发生了变化.缺陷对载流子越过栅氧化层势垒有辅助作用,从而导致栅漏电的增加.深能级瞬态谱测试结果表明中子辐照还会导致MOSFET器件沟道附近SiC材料中本征缺陷状态的改变,同时形成了新的Si空位缺陷能级,但这些缺陷不是导致器件性能退化的主要原因.In this paper,the displacement damage degradation characteristics of silicon carbide(SiC)Schottky barrier diode(SBD)and metal oxide semiconductor field effect transistor(MOSFET)are studied under 14-MeV neutron irradiation.The experimental results show that the neutron irradiation with a total fluence of 1.18×10^(11)cm^(-2)will not cause notable degradation of the forward I-V characteristics of the diode,but will lead to a significant increase in the reverse leakage current.A defect with energy level position of E_(C)−1.034 eV is observed after irradiation by deep level transient spectroscopy(DLTS)testing,which is corresponding to the neutron-induced defect cluster in SiC.This deep level defect may cause the Fermi level of n-type doping drift region to move toward the mid-gap level.It ultimately results in the decrease of the Schottky barrier and the increase of the reverse leakage current.In addition,neutron-induced gate leakage increase is also observed for SiC MOSFET.The gate current corresponding to V_(gs)=15 V after irradiation increases nearly 3.3 times that before irradiation.The donor-type defects introduced by neutron irradiation in the oxide layer result in the difference in the conductivity mechanism of gate oxygen between before and after irradiation.The defects have an auxiliary effect on carrier crossing the gate oxide barrier,which leads to the increase of gate leakage current.The defects introduced by neutron irradiation are neutral after capturing electrons.The trapped electrons can cross a lower potential well and enter the conduction band to participate in conduction when the gate is positively biased,thus causing the gate current to increase with the electric field increasing.After electrons captured by donor-type defects enter the conduction band,positively charged defects are left from the gate oxide,leading to the negative shift of the transfer characteristics of SiC MOSFET.The results of DLTS testing indicate that the neutron irradiation can not only cause the intrinsic defect state of S

关 键 词：碳化硅功率器件 中子辐照 位移损伤 深能级瞬态谱 

分 类 号：TN386[电子电信—物理电子学]