Low-Voltage Scanning Electron Microscopy as a Tool for Surface Imaging and Analysis of Practical Materials

Abstract

Low-voltage scanning electron microscopy (LV-SEM), imaging and energy dispersive x-ray spectroscopy (EDX) analysis, have been applied to steel surfaces in order to clarify the performance of these techniques as a surface analysis. The information depth of LV-SEM imaging is limited by the penetration range of primary electrons. The range also limits the information depth of LV-SEM-EDX analysis. These situations are quite different from those of surface analysis techniques such as Auger electron microscopy in which the escape depth of signal electrons determines the information depth. The information depths of both LV-SEM imaging and LV-SEM-EDX analysis are an order of 10 nm for the primary electron energy of around 1 keV. We can obtain topographic, material, and elemental information from such shallow region of material surfaces with high spatial resolution. This shows that the techniques are applicable to surface analysis of practical materials although the information depth is still deeper by one order than those of the conventional surface analysis techniques.

ULV-SEM-EDX analysis of fine precipitates in Cr-Mo steel using windowless silicon-drift detector

“…We show the fine precipitates in steel material are imaged and identified by ULV-SEM-EDX analysis by detecting low energy x-rays using the windowless SSD system. This is a big advantage of the technique as well as thin surface analysis [3]. The spatial resolution roughly estimated from Fig.2 is less than 20 nm.…”