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Quantitative evaluation of AES‐depth profiles of thin anodic oxide films (Ta 2 O 5 /Ta, Nb 2 O 5 /Nb)
Author(s) -
Sanz J. M.,
Hofmann S.
Publication year - 1983
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740050507
Subject(s) - sputtering , analytical chemistry (journal) , oxide , ion , metal , oxygen , materials science , thin film , chemistry , metallurgy , nanotechnology , organic chemistry , chromatography
Thin films of anodically formed Ta 2 O 5 and Nb 2 O 5 on polycristalline Ta and Nb, respectively, are analysed with AES during sputtering with Ar + ions at energies between 0.5 keV and 5 keV. A sputtering induced depletion of oxygen at the surface is observed in both oxides. The kinetics of this depletion and the steady‐state composition at the surface of the samples are studied as a function of the primary ion energy. The results are interpreted using a modification of the model of Ho et al. (1976) for the preferential sputtering of alloys. The thickness of the transient layer increases non‐linearly from 1.6 to 3.4 nm with increasing ion energy. Below 2 keV, the surface depletion of oxygen increases with decreasing ion energy and is constant above 2 keV up to 5 keV. The results are similar for both oxides. At 2 keV, the minimum measured width of the oxide/metal interface is 2 nm for Ta 2 O 5 /Ta and is about two times larger for Nb 2 O 5 /Nb. In both cases it increases with the square root of the ion energy and it is independent on the oxide layer thickness between 10 nm and 150 nm.