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 imag es of high-angle annular dark held scanning transmission electron microscop y with a tightly focused electron probe. The images show characteristic exc ess brightness depending on the number of arsenic atoms per atomic column. Through a simple analysis capable of identifying the number of arsenic atom s in an atomic column by using the above characteristic brightness, the qua ntitative two-dimensional distribution of arsenic atoms can be successfully obtained at atomic resolution, being consistent with the secondary ion mas s spectroscopy and Rutherford backscattering spectroscopy measurements. Thi s method is the only capable technique for detecting impurity atoms in ever y atomic column.