Sputtering and radiation-enhanced segregation in amorphous CuTi alloys

Binary amorphous copper-titanium alloys of compositions 44, 53, 65 and 69 at% copper were sputtered with 2 keV Ar + ions. The surface concentrations were then determined by Auger electron spectroscopy and ion scattering spectrometry. It was found that Cu is sputtered preferentially as it segregates...

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Bibliographic Details
Published in:Surface science 1991-08, Vol.254 (1), p.73-80
Main Authors: van Wyk, G.N., du Plessis, J., Taglauer, E.
Format: Article
Language:English
Subjects:
Condensed matter: structure, mechanical and thermal properties
Exact sciences and technology
Ion radiation effects
Physical radiation effects, radiation damage
Physics
Structure of solids and liquids
crystallography
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Summary:Binary amorphous copper-titanium alloys of compositions 44, 53, 65 and 69 at% copper were sputtered with 2 keV Ar + ions. The surface concentrations were then determined by Auger electron spectroscopy and ion scattering spectrometry. It was found that Cu is sputtered preferentially as it segregates to the surface. A recently developed model for radiation-enhanced surface segregation was used to fit the experimental data. The segregation energy decreases with increasing Cu concentration from 2500 Jmol −1 to zero for the highest concentration, in qualitative agreement with several predictions on the segregating species in the alloy. The radiation-enhanced diffusion coefficients have values in the range (2–3) × 10 −20 m 2 s . From the concentration profiles the depth of the altered layer was estimated to about 4 nm which coincides well with the range of the defect distribution caused by the argon ions according to TRIM calculations. A Cu Ti sputtering ratio of 6 was needed for the best possible fit of the results.
ISSN:0039-6028
1879-2758
DOI:10.1016/0039-6028(91)90639-A