Low-energy grazing-angle argon-ion irradiation of silicon: A viable option for cleaning?

In recent publications, it has been suggested that atomically clean, flat, crystalline silicon surfaces can be obtained by low-energy (0.1–1 keV) oblique-angle (⩾45° off-normal) argon-ion bombardment at mildly elevated target temperatures (∼500 °C). Here, this procedure has been applied to a multiple boron delta-doped Si structure. It leads to a massive relocation of subsurface doping atoms because of the accompanying injection of point defects into the bulk. This greatly affects the usefulness of the proposed cleaning method and shows that it is hazardous to base claims of quality solely on results obtained with surface-sensitive (∼1 nm) analytical techniques.