Experimental evaluation of interfaces using atomic-resolution high angle annular dark field (HAADF) imaging

摘要: Aberration-corrected high angle annular dark field (HAADF) imaging in scanning transmission electron microscopy (STEM) can now be performed at atomic-resolution. This is an important tool for the characterisation of latest semiconductor devices that require individual layers to grown accuracy a few atomic layers. However, actual quantification interfacial sharpness atomic-scale complicated matter. For instance, it not clear how use total, column or background HAADF signals affect measured layer widths. Moreover, reliable and consistent method measurement necessary. To highlight these issues, two types AlAs/GaAs interfaces were studied in-depth by atomic-resolution imaging. A analysis was developed order map various across image reliably determine sharpness. The results demonstrated level perceived vary significantly with specimen thickness choice signal. Individual widths also shown have some dependence on Hence, crucial awareness which part signal chosen along possible effects future studies scale