Energy distribution of secondary ions from 15 polycrystalline targets

Fifteen metallic and semiconductor polycrystalline targets of 99.9% purity were bombarded with an Ar+ ion beam of 40 keV energy. The energy distribution of different kinds of secondary ions of basic target material (atomic and molecular, positively and negatively charged), as well as of negative ions (C−, C− 2, O− and O− 2) formed by sputtering the surface impurities from bombarded targets was measured. The energy distribution of secondary ions was measured in the range of E 2 > 1 eV. The upper measurement limit depended on the yield of observed ion species and it reached E 2 < 3000 eV. The shape of the energy distribution curves could be explained satisfactorily by the law for the nonadiabatic emission process.