Interface mixing of Fe/Si bilayers by noble-gas ions: Are there effects of the ionic charge state?

Charge-state equilibration of ions moving in matter occurs within femtoseconds and when penetrating nanometer depths. Ion-beam mixing in bilayers, tens of nm thick, should therefore not depend on the charge state of the projectiles. As the experimental situation for metal/silicon bilayers irradiated with noble-gas ions of different charge-states is ambiguous, we studied interface mixing of Fe/Si(1 0 0) bilayers, induced by 100 keV Ar-40, 180 keV Kr-86 and 250 keV Xe-132 ions, either singly and multiply charged (Ar8+, Kr11+, Xe17+). No significant influence of the ionic charge-state was established for Kr and Xe ions; a slightly higher mixing rate was found for Ar8+ than for Ar1+ irradiation. (c) 2007 Elsevier B.V. All rights reserved.15th International Conference on Ion Beam Modification of Materials, Sep 18-22, 2006, Taormina, Ital