Two-dimensional distribution of As atoms doped in a Si crystal by atomic-resolution high-angle annular dark field STEM

Observation of arsenic doped silicon has been made by using Z-contrast images of high-angle annular dark held scanning transmission electron microscopy with a tightly focused electron probe. The images show characteristic excess brightness depending on the number of arsenic atoms per atomic column. Through a simple analysis capable of identifying the number of arsenic atoms in an atomic column by using the above characteristic brightness, the quantitative two-dimensional distribution of arsenic atoms can be successfully obtained at atomic resolution, being consistent with the secondary ion mass spectroscopy and Rutherford backscattering spectroscopy measurements. This method is the only capable technique for detecting impurity atoms in every atomic column.