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Optimum parameters for combined Auger‐ionization loss coincidence spectroscopy in the reflection mode
Author(s) -
Gergely G.
Publication year - 1992
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.740190104
Subject(s) - coincidence , auger electron spectroscopy , spectroscopy , spectrometer , atomic physics , electron , detector , optics , ionization , analytical chemistry (journal) , physics , chemistry , nuclear physics , medicine , ion , alternative medicine , pathology , quantum mechanics , chromatography
The detection limit of AES can be improved by combined Auger‐electron loss coincidence spectroscopy (AES‐ILSCS) as proposed by Cazaux. Using an arrangement with two hemispherical analysers and large‐angle collectors, experimental parameters are optimized by (1) matching the energy windows Δ E s of the spectrometers to achieve a large peak/background ratio, (2) setting the angular positions to obtain identical sampling depths for AES and ILS and (3) tilting the sample and using an adjustable electron gun at glancing incidence to get a large ILS signal. False coincidence can be reduced by small Δ E s and using very fast detectors in the coincidence mode for post‐accelerated AES and ILS electrons. Based on Langeron's data, the estimated coincidence signal/false coincidence noise ratio is ∼1 for 10 −4 Fe coverage on an Si substrate using 9 keV, 10 nA primary electrons and a Δ t ≈1 ns coincidence interval. The detection limit can be improved by a factor of 10 2 with respect to conventional AES.