Dynamic SIMS - CasaXPS

CasaXPS Manual 2.3.15 Rev 1.0
Copyright © 2010 Casa Software Ltd
assumes the data obeys Passion statistics, but otherwise varies smoothly; it is
clear from Figure 14 that the mass-binned data contains anomalous values.
Peak Fitting ToF SIMS Data
The features in CasaXPS typically used to model XPS data envelopes can also
be used to analyst overlapping peaks in high resolution ToF SIMS spectra. The
principal difference between ToF SIMS and XPS is that asymmetry in ToF
SIMS peaks is, in general, in the opposite direction to that found for XPS
peaks. As a result, not all line-shapes in CasaXPS are appropriate for ToF SIMS
peaks, however the more recently introduced asymmetric line-shapes of LA
and LF provide a means of creating line-shapes appropriate for the range of
ToF SIMS peaks observed in practice.
The data in Figure 15 illustrates the similarities between XPS and ToF SIMS,
where the mass peaks associates with a nominal mass of 42 are very typical
of polymer XPS spectra such as PMMA or PET. The problems of
understanding the data are also similar in that both the position and the
intensity of the underlying peaks are of importance when identifying the
molecular ions responsible for the measured data.
Figure 15: Example of ToF SIMS peak structure.
The procedure for adding synthetic components to the data involves first
adding a quantification region to the data with background type set of “Zero”
before adding synthetic line-shapes. Creating and adjusting regions and
components is performed on the Quantification Parameters dialog window
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