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The metastable decomposition of sputtered, mass-selected, cluster ions is investigated under ultrahigh-vacuum conditions. Highly excited $\mathrm{Al}_{n}^{}{}_{}{}^{+}$ and $\mathrm{Cu}_{n}^{}{}_{}{}^{+}$ cluster ions are found to decompose mainly by evaporation of single neutral atoms, whereas for $\mathrm{Si}_{n}^{}{}_{}{}^{+}$ clusters, fission is also observed. The decay rates of $\mathrm{Cu}_{n}^{}{}_{}{}^{+}$ clusters are in agreement with calculations presented by Klots. Some consequences of our results for the interpretation of cluster-ion mass spectra produced by other experimental methods are discussed.

The topography induced by 7 keV particle bombardment of Si substrates has been measured dynamically as a function of particle fluence with a B11 source coupled into a scanning electron microscope. Distinctive differences are observed according to particle species used (Ar, Kr or O) and flux incidence angle to the surface. Strategies for morphology development minimization are discussed and the relevance of the study to sputter profiling and lithographic etching outlined.

High depth resolution Rutherford backscattering-channelling has been employed to assess the depth of damage and the increase in total damage with increasing ion fluence over the range 1014-1016 ions cm−2 for 5 keV A+ implants into Si conducted under low flux density and UHV conditions. It is shown that damage-depth estimates for zero fluence conditions are similar to theoretical predictions and that the increasing damaged (amorphised layer) depth with increasing fluence is the result of continuing damage accumulation deeper in the Si.

Mass separated metal and silicon cluster ion beams M+,− n are produced by sputtering and undergo fragmenting and/or neutralizing collisions at different kinetic energies (100-1800 eV) in Ar and SF6. Fragment patterns induced by rare gas collisions open a way to determine ionization potentials and electron affinities of clusters. These values are compared to known experimental and theoretical data. For negatively charged clusters the absorption in gas targets is mainly due to neutralization, the cross sections varying with cluster material, number of atoms and collision partner from 10 A2 to about 50 A2.