Specific Process Knowledge/Characterization/XPS/Processing/ALDSandwich1/2Survey: Difference between revisions
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= Survey spectrum processing = | = Survey spectrum processing = | ||
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In the automatic peak fitting routine, a background is added to the data below each peak. This background is then subtracted before the peak is fitted, it is shown with a light green color. It is clear that something goes wrong; the fitted background eats up the majority of the peak. The result is that the fitted Ti2p peak is much too small - then oxygen is seen as the only peak in the spectrum. | In the automatic peak fitting routine, a background is added to the data below each peak. This background is then subtracted before the peak is fitted, it is shown with a light green color. It is clear that something goes wrong; the fitted background eats up the majority of the peak. The result is that the fitted Ti2p peak is much too small - then oxygen is seen as the only peak in the spectrum. | ||
Judging by the way the background is fitted, it looks as if the software is programmed to fit the background below only the Ti2p<sub>3/2</sub> peak. The other part of the spin couple (the Ti2p<sub>1/2</sub> peak) is some 6 eV away on the | Judging by the way the background is fitted, it looks as if the software is programmed to fit the background below only the Ti2p<sub>3/2</sub> peak. The other part of the spin couple (the Ti2p<sub>1/2</sub> peak) is some 6 eV away on the higher binding energy side. Knowing that titanium will oxidize completely if oxygen is present we can expect only to see Ti<sup>4+</sup>. However, since the sputtering of the surface by Ar ions will usually act as mildly reducing, we can expect that intermediate oxidation steps of Ti will appear as the TiO<sub>2</sub> is sputtered. These intermediate states will cause the expected dip between the two peaks of the Ti2p(<sup>4+</sup>) spin orbit couple to disappear and the fitting of the background goes wrong. | ||
What to do about this? | |||
# Continue with the fitting of the high resolution scans - here we will have a much better chancer to work with the fitting of the peaks with intermediate oxidation steps. | |||
# Use a [https://xpssimplified.com/magcis_ion_system.php MAGCIS gas cluster ion source] instead in another instrument to avoid the reducing action of the Ar (single) ion source. | |||
The analysis continues [[Specific Process Knowledge/Characterization/XPS/Processing/ALDSandwich1/3scanned|'''here''']]. | |||