Electronic and nuclear thermal spike effects in sputtering of metals with energetic heavy ions

Sputtering yields and typical angular distributions of pure metals were measured with heavy ions at energies where electronic energy loss dominates. Using different ion charge states and ion/energy combinations, electronic effects were observed in sputtering of metals such as Ti and Zr, but not for Au. An inelastic thermal spike model was extended to calculate sputtering by particle evaporation from an ion track, however, to reproduce the measured yields, besides electronic also elastic collision (nuclear) spike effects had to be included. The results demonstrate the importance and synergism of both heating mechanisms for sputtering in this energy regime.