非对称沟槽SiC MOSFET单粒子栅穿机理研究  

Study on Single-event Gate Rupture Mechanism of Asymmetric-trench SiC MOSFET

作　　者：王立昊 董涛 方星宇 戚晓伟 王亮 陈淼 张兴[1] 赵元富 WANG Lihao;DONG Tao;FANG Xingyu;QI Xiaowei;WANG Liang;CHEN Miao;ZHANG Xing;ZHAO Yuanfu(Peking University,Beijing 100871,China;Beijing Microelectronics Technology Institute,Beijing 100076,China)

机构地区：[1]北京大学,北京100871 [2]北京微电子技术研究所,北京100076

出　　处：《原子能科学技术》2025年第4期957-965,共9页Atomic Energy Science and Technology

摘　　要：新型航天器对千伏级抗辐照SiC器件有迫切需求,为了给SiC MOSFET抗单粒子栅穿加固设计提供理论依据,对1 200 V非对称沟槽SiC MOSFET开展了单粒子栅穿效应研究。试验结果表明,在200 V、300 V的漏极偏置电压下进行辐照,辐照期间和辐照后器件均出现了泄漏电流退化。TCAD仿真显示,沟道下方栅极沟槽拐角处的瞬时电场超过了临界击穿电场值。然而被P-well包围的栅极沟槽拐角,由于重掺杂P型区对空穴的快速抽取作用,该处的瞬时电场未达到临界击穿电场值。FIB-SEM结果证实了沟道区下方栅极沟槽拐角处的氧化层被击穿,产生漏极至栅极的泄漏电流路径。沟槽栅SiC MOSFET的抗单粒子栅穿加固设计,应重点关注栅极沟槽拐角和沟槽底部处,利用P型区包围沟槽拐角可以缓解单粒子导致的电场集中效应。The demand for kilovolt-level radiation-hardened SiC devices in modern spacecraft is urgent.To provide a theoretical basis for the hardening design of SiC MOSFETs against single-event gate rupture (SEGR),a study on the single-event effects of 1 200 V asymmetric-trench SiC MOSFETs was conducted,analyzing the physical mechanisms of SEGR.The experimental samples were commercially available 1 200 V asymmetric-trench SiC MOSFETs.The heavy ion irradiation experiments were performed at Heavy Ion Research Facility in Lanzhou (HIRFL).The heavy ions used in the experiment were Ta ions,with a linear energy transfer (LET) value of 78.7 Me V/(mg/cm^(2)) and a range of 80.5μm in SiC material.During the experiment,two source measure units (SMUs) were employed to apply drain bias and gate bias,respectively,while monitoring and recording the drain leakage current (I_D) and gate leakage current (I_G).The gate bias was set to 0 V to maintain the device under test in the off-state,while the drain bias was set to a constant positive value to study the effects of drain bias on irradiation damage.In each irradiation process,the ion fluence rate was set to approximately 1×10~4 cm^(-2)·s^(-1),with a total fluence of 1×10~6 cm^(-2).The experimental results show that both I_(D) and I_(G) exhibit degradation during irradiation at drain bias voltages of 200 V and 300 V.Additionally,I_(D) and I_(G) increase at the same rate as the heavy ion fluence increased.The post-irradiation measurements of the drain and gate characteristics are consistent with the trends observed during irradiation.TCAD simulations indicate that the transient electric field at the trench gate corner beneath the channel exceeds the critical breakdown field,and the damage to the gate oxide is identified as the primary cause of the leakage current degradation.However,at the trench gate corner surrounded by the P-well,the heavy doping of the P-type region facilitates the rapid extraction of holes,resulting in a weaker electric field concentration effect that does not rea

关 键 词：碳化硅 MOSFET 单粒子效应 单粒子栅穿 辐照效应 

分 类 号：TL99[核科学技术—核技术及应用] TN406[电子电信—微电子学与固体电子学]