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Influence of interfacial depth on depth resolution during GDOES depth profiling analysis of thin alumina films
Author(s) -
Shimizu K.,
Habazaki H.,
Skeldon P.,
Thompson G. E.,
Marcus R. K.
Publication year - 2001
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.1120
Subject(s) - sputtering , impact crater , materials science , analytical chemistry (journal) , resolution (logic) , thin film , optics , chemistry , nanotechnology , astronomy , artificial intelligence , computer science , physics , chromatography
Factors controlling the depth resolution in radio frequency glow discharge optical emission spectroscopy (rf‐GDOES) depth profiling analysis of thin films have been investigated using anodic alumina films of varying thicknesses with delta function marker layers of ∼2 nm width located at various depths from the oxide surface. In rf‐GDOES depth profiling analysis, where a relatively large area of ∼4 mm in diameter is analysed, it was found that the depth resolution is determined mainly by the large‐scale variation of sputtering rate across the crater. Despite the relatively large area analysed, the uniformity of sputtering rate across the crater was constant to within 1% under the optimum Ar pressure except for near‐edge regions of ∼0.4 mm width, where the sputtering rate was ∼6% higher than in the central crater region. Owing to this relatively minor non‐uniformity of sputtering rate, the depth resolution degrades approximately linearly with depth. A depth resolution of ∼1.3 nm was realized to depths of ∼25 nm, where the degradation of depth resolution due to the non‐uniformity in sputtering rate is insignificant. The depth resolution is close to the ultimate depth resolution in sputter depth profiling, claimed to be 0.7– 1.0 nm, and arises from the minimal atomic mixing associated with film sputtering with Ar + ions of very low energy, ∼50 eV, in rf‐GDOES analysis. Copyright © 2001 John Wiley & Sons, Ltd.