SiC MOSFET栅极电参数退化机理及耦合关系  

Degradation Mechanism and Coupling Relationship of Gate Electrical Parameters of SiC MOSFETs

作　　者：孟鹤立 邓二平 常桂钦 黄永章 Meng Heli;Deng Erping;Chang Guiqin;Huang Yongzhang(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(NCEPU),Beijing 102206,China;Zhuzhou CRRC Times Semiconductor Co.,Ltd..,Zhuzhou 412001,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京102206 [2]株洲中车时代半导体有限公司,湖南株洲412001

出　　处：《半导体技术》2022年第1期9-18,共10页Semiconductor Technology

基　　金：国家自然科学基金资助项目(52007061)。

摘　　要：栅极一直是SiC MOSFET可靠性研究的重点,栅极老化过程中电参数之间的耦合关系对栅极可靠性研究有至关重要的作用。为此,搭建了能够同时监测阈值电压和栅极漏电流的高温栅偏(HTGB)试验平台。研究了HTGB下阈值电压和漏电流的退化趋势和影响,基于氧化层注入电荷量深入分析了两者之间的耦合关系。结果表明,热应力对载流子隧穿影响较为明显,对陷阱捕获的载流子影响相对较小,而场强则对两者均具有显著的影响。此外,提出了减小阈值电压漂移对SiC MOSFET均流特性影响的方法,指出了栅极漏电流下降现象的本质是栅极陷阱充电,并给出了栅极老化过程中漏电流失效基准值选取的方法。该研究结果为深入理解SiC MOSFET的栅极失效机理提供了理论指导。The gate has always been the key to the reliability research of SiC MOSFETs.The coupling relationship between electrical parameters during the gate aging process plays an important role in the reliability research of the gate.Therefore,a high-temperature gate bias(HTGB)test platform was built,which can monitor the threshold voltage and the leakage current of the gate at the same time.The degradation trend and influence of threshold voltage and leakage current under HTGB were studied.And the coupling relationship between threshold voltage and leakage current was deeply analyzed based on the amount of charge injected into the oxide layer.The results show that the thermal stress has an obvious effect on the carrier tunneling and a relatively less effect on the trapped carrier,while the field strength has a significant effect on both of them.In addition,the methods to reduce the influences of threshold voltage drift on the current sharing characteristics of SiC MOSFETs were proposed.It is pointed out that the essence of the decline of gate leakage current is gate trap charging,and the methods of selecting the reference value of leakage current failure in the process of gate aging were given.The research results provide theoretical guidance for further understanding the gate failure mechanism of SiC MOSFETs.

关 键 词：均流特性 阈值电压 漏电流 SiC MOSFET 高温栅偏(HTGB)试验 

分 类 号：TN386.1[电子电信—物理电子学] TN304.24