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O 2 + probe‐sample conditions for ultra low energy SIMS depth profiling of nanometre scale Si 0.4 Ge 0.6 /Ge quantum wells
Author(s) -
Morris R. J. H.,
Dowsett M. G.,
Beanland R.,
Dobbie A.,
Myronov M.,
Leadley D. R.
Publication year - 2013
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.4963
Subject(s) - nanometre , analytical chemistry (journal) , germanium , chemistry , atomic physics , silicon , physics , optics , chromatography , organic chemistry
The O 2 + probe‐sample conditions and subsequent data analysis required to obtain high depth resolution SIMS depth profiles from Si 1− x Ge x /Ge quantum well structures (0.6 ≤ x ≤ 1) are presented. For primary beam energies E p >500 eV and x approaching 1, a significant decrease in the Ge + ionisation probability resulted in unrepresentative and unquantifiable depth profiles. For E p ≤ 500 eV, a monotonic increase in the Ge + signal with x was observed resulting in profiles representative of the sample structure and enabling x to be found. A depth scale was also established using a point‐by‐point approach taking into account the local erosion rate, which is a function of x . Both the composition and the thickness of the Si 1− x Ge x and Ge layers were found to be in excellent agreement with those obtained using X‐ray and transmission electron microscopy. Copyright © 2012 John Wiley & Sons, Ltd.