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Improved dynamic range and automated lineshape differentiation in AES/XPS composition versus depth profiles
Author(s) -
Watson D. G.
Publication year - 1990
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.740150904
Subject(s) - spectral line , range (aeronautics) , computational physics , basis (linear algebra) , spectrum (functional analysis) , chemistry , set (abstract data type) , operator (biology) , intensity (physics) , data set , analytical chemistry (journal) , mathematics , optics , statistics , physics , materials science , geometry , computer science , biochemistry , repressor , astronomy , chromatography , transcription factor , composite material , gene , programming language , quantum mechanics
Depth profiles calculated using simple peak‐to‐peak or peak height or area measurements are subject to inaccuracies caused by spectral noise, sloping backgrounds and possibly by overlapping spectra of different elements or chemical species. An automated program that reduces or eliminates the effects of these potential sources of error in the peak heights and areas calculated from electron spectra has been developed. The program uses linear least‐squares fitting of one or more basis spectra to determine the peak height or area for each spectrum recorded during the profile. The program selects the basis spectra from the energy region data set without operator intervention. The number of unique lineshapes is determined by the program, again without operator intervention, and a profile is calculated for each species. The fit method of intensity determination was found to increase the dynamic range by reducing false contributions to the calculated intensities; this observation holds when a single basis spectrum is sufficient to model the data. Contributions from overlapping spectra are resolved if an example of each pure species lineshape is available in the regional data set. The method is demostrated by practical example.