Crystallographic orientation dependence of SEM contrast revealed by SiC polytypes
Crystallographic orientation dependence of SEM contrast revealed by SiC polytypes
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DOI：
10.1116/1.4927136
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发表时间：
2015-07-01
影响因子：
1.4
通讯作者：
Kaneko, Tadaaki
中科院分区：
文献类型：
--
作者：
Ashida, Koji;Kajino, Tomonori;Kaneko, Tadaaki
在一次电子能量小于1.0 keV的低能扫描电镜（SEM）下，以具有确定电子穿透深度标记层的4H-SiC（0001）为标准样品，研究了1.0 nm深度范围内扫描电镜对比度对晶体取向的依赖性。利用常规的Everhart-Thornley型室内探测器，通过调整样品的倾斜和旋转角度，观察到最上层两个硅碳双层层（深度为0.50 nm）堆叠顺序方向的差异，从而观察到清晰的亮暗对比。结果表明，当入射初级电子束方向几乎与最顶层的叠加序列方向平行时，发射的信号更亮。通过将无六方位的3C-SiC（111）的低能SEM对比与其电子背散射衍射图进行对比，分别验证了这种角度重合。所得结果表明，在不使用任何特殊探测器的情况下，低能电子可以表征表面下的晶体取向。(C) 2015年美国真空学会。
In low energy scanning electron microscope (SEM) with primary electron energy less than 1.0 keV, the dependence of SEM contrast on crystallographic orientation within a range of 1.0 nm in depth has been investigated by utilizing 4H-SiC (0001) as a standard sample having a definitive electron penetration depth marker layer at hexagonal sites. Reflecting the difference of the direction of topmost two Si-C bilayers stacking sequence (0.50 nm in depth), clear bright and dark SEM contrast has been observed by adjusting the sample tilting and rotation angles by a conventional Everhart-Thornley type in-chamber detector. It is revealed that the brighter signal emission arises when the incident primary electron beam direction is almost parallel to the topmost stacking sequence direction. This angular coincidence was verified separately by correlating low energy SEM contrast from 3C-SiC (111) of no hexagonal sites with its electron back scattered diffraction pattern for identifying stacking sequence direction. The obtained results suggest a potential of low energy electron to characterize the crystallographic orientation just beneath the surface without using any special detector. (C) 2015 American Vacuum Society.