扫描电子显微镜成像方法的研究

STUDIES ON IMAGING STRATEGY IN THE SCANNING ELECTRON MICROSCOPE

本文从五个方面详细讨论了选择扫描电镜最佳成像参数的方法。并通过对两种纯元素对样品的原子序数反差的计算得到两点结论:(1)当两元素的原子序数差减小时,其图像的空间分辨迅速提高。(2)在快速帧速率下视频寻找成像区域时,为了分辨出图像中低于1％的反差水平,束流需达500nA束斑直径达1μm或更大些。

A strategy of choosing the operating parameters for optimal imaging with scanning electron microscope is described in this paper. Specific calculations for the case of atomic number contrast between pure element couples obtain two conclusions; 1) The limiting spatial resolution increases rapidly as the difference in atomic number decreases. 2) For visual searching of image fields at rapid frame rates,beam currents as high as 500 nA and beam diameters of 1 micrometer or more are necessary to gletect contrast levels below 1 percent.