Li Dongxun, Zhang Yuming, Tang Xiaoyan, He Yanjing, Yuan Hao, Jia Yifan, Song Qingwen, Zhang Ming, Zhang Yimen
School of Microelectronics, Xidian University, The State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, Xi'an 710071, China.
School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, China.
Nanomaterials (Basel). 2020 Jul 8;10(7):1332. doi: 10.3390/nano10071332.
In this paper the effects of 5 MeV proton irradiation on nitrided SiO/4H-SiC metal-oxide-semiconductor (MOS) capacitors are studied in detail and the related mechanisms are revealed. The density of interface states (Dit) is increased with the irradiation doses, and the annealing response suggests that the worse of Dit is mainly caused by displacement effect of proton irradiation. However, the X-rays photoelectron spectroscopy (XPS) measurement shows that the quantity proportion of breaking of Si≡N induced by displacement is only 8%, which means that the numbers of near interface electron traps (NIETs) and near interface hole traps (NIHTs) are not significantly changed by the displacement effect. The measurements of bidirectional high frequency (HF) C-V characteristics and positive bias stress stability show that the number of un-trapped NIETs and oxide electron traps decreased with increasing irradiation doses because they are filled by electrons resulted from the ionization effect of proton irradiation, benefiting to the field effective mobility (μ) and threshold voltage stability of metal-oxide-semiconductor field-effect transistors (MOSFETs). The obviously negative shift of flat-band voltage (V) resulted from the dominant NIHTs induced by nitrogen passivation capture more holes produced by ionization effect, which has been revealed by the experimental samples with different nitrogen content under same irradiation dose.
本文详细研究了5 MeV质子辐照对氮化SiO/4H-SiC金属氧化物半导体（MOS）电容器的影响，并揭示了相关机制。界面态密度（Dit）随辐照剂量增加而增大，退火响应表明Dit变差主要是由质子辐照的位移效应引起的。然而，X射线光电子能谱（XPS）测量表明，由位移引起的Si≡N键断裂的数量比例仅为8%，这意味着近界面电子陷阱（NIETs）和近界面空穴陷阱（NIHTs）的数量不会因位移效应而显著变化。双向高频（HF）C-V特性和正偏压应力稳定性的测量表明，未捕获的NIETs和氧化物电子陷阱的数量随辐照剂量增加而减少，因为它们被质子辐照电离效应产生的电子填充，这有利于金属氧化物半导体场效应晶体管（MOSFETs）的场有效迁移率（μ）和阈值电压稳定性。由氮钝化诱导的主要NIHTs捕获更多电离效应产生的空穴，导致平带电压（V）明显负移，这已被相同辐照剂量下不同氮含量的实验样品所揭示。
