电子辐照对SiC功率MOSFET器件动态特性的影响机理  

Impact of Electron Irradiation on Dynamic Characteristics of SiC Power MOSFETs

作　　者：付祥和 赵小龙[1,2] 彭文博 郭书文[1,2] 蔡亚辉 贺永宁 FU Xianghe;ZHAO Xiaolong;PENG Wenbo;GUO Shuwen;CAI Yahui;HE Yongning(Faculty of Electronic and Information Engineering,Xi’an Jiaotong University,Xi’an 710049,China;The Key Lab of Micro-Nano Electronics and System Integration of Xi’an City,Xi’an 710049,China)

机构地区：[1]西安交通大学电子与信息学部,西安710049 [2]西安市微纳电子与系统集成重点实验室,西安710049

出　　处：《西安交通大学学报》2022年第11期95-103,共9页Journal of Xi'an Jiaotong University

基　　金：国家重点研发计划资助项目(2020YFB0407800)。

摘　　要：针对SiC功率场效应晶体管在太空、核工业等高能粒子辐照环境下应用时的老化失效问题,以1200 V SiC MOSFET器件为对象,研究了电子辐照对SiC MOSFET器件动态特性影响及机理。在10 MeV电子束下对SiC MOSFET器件进行200 kGy剂量的辐照;然后,采用双脉冲测试电路对SiC MOSFET器件进行开关测试,并提取开关速度以及开关瞬态能量损耗等参数;接着对器件进行静态特性测试得到器件的阈值电压、栅极电阻、寄生电容等参数;最后,对比辐照与未辐照器件动态和静态特性参数变化分析电子辐照对SiC MOSFET器件动态特性影响机理。分析结果表明:在漏极电压800 V、漏极电流15 A、栅极外接电阻200Ω的测试条件下,辐照后器件开启延迟时间减小11.6 ns,开启瞬态能量损耗减小0.18μJ,关断延迟时间增大48.4 ns,关断瞬态能量损耗增大0.11μJ。结合器件静态特性参数分析发现:辐照后氧化层中正固定电荷增加7.14×10^(11)cm^(-2),器件阈值电压减小1.5 V;电子辐照在氧化层中电离产生电子空穴对,氧化层陷阱捕获空穴形成带正电的固定电荷,使得器件阈值电压减小,这是导致器件在电子辐照后开启速度变快,关断速度变慢的主要原因。该研究结果可为SiC功率器件在辐照环境中的应用以及制造厂商提高SiC MOSFET在辐照环境中的可靠性提供一定的参考。This paper studies the impact of electron irradiation on the dynamic characteristics of 1200 V SiC MOSFETs and the corresponding mechanism in an attempt to tackle the aging of SiC power field-effect transistors used in high-energy particle irradiation applications such as the space and nuclear industry.First,the SiC MOSFET is irradiated with a dose of 200 kGy under 10 MeV electron beam.Then the SiC MOSFET is tested for switching in a double-pulse test circuit,and parameters such as switching speed and switching transient energy loss are recorded.After that,the static characteristics of the device are tested to obtain the threshold voltage,gate resistance,parasitic capacitance and other parameters.Finally,the impact of electron irradiation on the dynamic characteristics of SiC MOSFETs is analyzed by comparing the dynamic and static characteristic parameters of irradiated and non-irradiated devices.The results show that the turn-on delay time of the irradiated device is reduced by 11.6 ns,the turn-on transient energy loss is reduced by 0.18μJ,the turn-off delay time increases by 48.4 ns,and the turn-off transient energy loss increases by 0.11μJ under a drain voltage of 800 V,a drain current of 15 A,and an external gate resistance of 200Ω.It is found that the positive fixed charge in the oxide layer increases by 7.14×10^(11)cm^(-2) after irradiation,and the threshold voltage of the device decreases by 1.5 V;ionizing electron irradiation in the oxide layer creates electron hole pairs and the oxide layer traps the holes and form positive fixed charges,which reduces the threshold voltage of the device.This is the main reason for faster turn-on and slower turn-off of the device after electron irradiation.The research results can provide some reference for the application of SiC power devices in the irradiation environment and for manufacturers to improve the reliability of SiC MOSFETs in the irradiation environment.

关 键 词：SiC功率器件 场效应晶体管 电子辐照 动态特性 

分 类 号：TN386.1[电子电信—物理电子学]