IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Engineering Tuesday Sessions
       Session SE-TuM

Paper SE-TuM9
Does Thermal Spike Effect Ion Mixing at Ion Energy Lower than 1.5 keV?

Tuesday, October 30, 2001, 11:00 am, Room 132

Session: Surface Engineering II: Cleaning, Modification, and Finishing
Presenter: M. Menyhard, Research Institute for Technical Physics and Materials Science, Hungary
Authors: M. Menyhard, Research Institute for Technical Physics and Materials Science, Hungary
G. Zsolt, Research Institute for Technical Physics and Materials Science, Hungary
P.J. Chen, National Institute of Standards and Technology
C.J. Powell, National Institute of Standards and Technology
L. Gal, National Institute of Standards and Technology
W.F. Egelhoff, National Institute of Standards and Technology
Correspondent: Click to Email
Experimentally measured (Auger, XPS) depth profiles cannot be properly evaluated without knowing the ion sputtering induced alteration. The presently used evaluation routines assume that ballistic mixing occur. It was suggested and some experimental evidences have been presented, however, long time ago, that the thermal spikes might be operating even at low ion energies causing enhanced mixing. Systematic studies on the appearance of thermal spikes in case of depth profiling applying low energy (less than 1.5 keV) ions sputtering has been carried out. Periodic double-layer structures (consisting 10 layer pairs) with double-layer thickness of 4 nm were grown by sputter deposition from pair of elements exhibiting high (Pt-Ti) and low solubility (Pt-Co, Ni-Ti, Co-Ti). Auger spectroscopic depth profiling was carried out with parameters of: specimen rotation, grazing angle of incidence, argon ions, energy range 0.3-1.5 keV. The ion mixing in these periodic structures can be measured by the amplitude of oscillation of the depth profile. The amplitude of oscillations in all cases was linearly dependent on the square roote of ion energy. Thus in the energy range studied a single mechanism was responsible for the ion mixing. Since we cannot suppose that at the 0.3 keV irradiation thermal spikes form it seems that the ion mixing in these cases are governed by ballistic mixing. The depth profiles were also simulated by T-DY4 code assuming ballistic mixing. The difference of the simulated and measured depth profiles was explained by interface roughness.