Energy distributions of secondary ions sputtered from aluminium and magnesium by Ne+, Ar+ and O2+: a comprehensive study

The energy distributions of positive and negative secondary ion species produced by 5 keV Ne+, Ar+ and O2+ ion bombardment at 30 degrees to polycrystalline aluminium and magnesium targets have been studied. The measurements were carried out in a small solid angle along the surface normal, without extracting ions into the mass–energy analyser. The most probable and average energies along with the widths of the distributions were tabulated; essential features of the spectra were interpreted in the terms of a linear collision cascade model with a knock-on contribution. Three energy sub-ranges with appreciable different energy power dependence E vs. s, which could approximate the experimental curves, were revealed for both Al+ and Mg+ atomic ions within a wide energy range. Nearly all the energy spectra of negative secondary ions demonstrated complex structure, with two distinct peaks, caused by impurity species with different binding energies.