Comparative study on slow-state near interface hole traps in NO and Ar annealed N-type 4H-SiC MOS capacitors by ultraviolet light
Comparative study on slow-state near interface hole traps in NO and Ar annealed N-type 4H-SiC MOS capacitors by ultraviolet light
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DOI：
10.1007/s10854-018-9563-5
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发表时间：
2018-07
期刊：
影响因子：
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通讯作者：
Yifan Jia;Hongliang Lv;Xiaoyan Tang;Qingwen Song;Yimen Zhang;Yuming Zhang;S. Dimitrijev;Jisheng Han
中科院分区：
文献类型：
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作者：
Yifan Jia;Hongliang Lv;Xiaoyan Tang;Qingwen Song;Yimen Zhang;Yuming Zhang;S. Dimitrijev;Jisheng Han
通过紫外光照射下随时间变化的偏应力，系统地研究了NO和Ar钝化n型4H-SiCMOS电容器的近界面电荷捕获和释放特性。Ar退火样品的平带电压不稳定性主要是由于电子直接隧穿进出近界面电子陷阱所致。然而，对于未退火的样品，近界面空穴陷阱(NIHTs)的空穴捕获也需要关注。研究发现，部分俘获空穴不容易从慢态近场高温超导中释放出来，这可能是作为正固定电荷而引起的阈值电压的不可恢复的负移。X射线光电子能谱分析表明，在NO处理后，一些中间氧化态转变为位于过渡层的强Si-≡-N和Si-Ox-Ny键，它们可能起到NIHTs的作用，甚至抑制了氢氟酸的腐蚀。因此，优化氮气处理对降低4H-SiCMOS器件中诱导的NIHTs密度具有重要意义。
The characteristics of near interface charge trapping and releasing on n-type 4H-SiC MOS capacitors with NO and Ar passivation have been systematically investigated through time-dependent bias stress with ultraviolet light irradiation. Flat band voltage instability of the Ar annealed samples mainly results from electrons directly tunneling in and out of the near interface electron traps. However, hole trapping by the near interface hole traps (NIHTs) also need to be concerned for the NO annealed samples. It is found that part of the trapped holes cannot be easily released from the slow-state NIHTs, which may act as the positive fixed charge and induce the unrecoverable negative shift of threshold voltage. The results from XPS show that after the NO annealing, some of the intermediate oxidation states are converted to the strong Si≡N and Si–Ox–Nybonds located in the transition layer, which may act as NIHTs and even suppress hydrofluoric acid etching. Thus, it is important to optimize nitrogen treatment in order to reduce the density of NIHTs induced in the 4H-SiC MOS devices.