Specific Process Knowledge/Characterization/XPS: Difference between revisions
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[[image:Si2p.JPG|420x420px|left|thumb|XPS Si2p spectrum of a Si reference sample (red curve), and a Si sample that was treated in HF shortly before the | [[image:Si2p.JPG|420x420px|left|thumb|XPS Si2p spectrum of a Si reference sample (red curve), and a Si sample that was treated in HF shortly before the measurement was done (green curve). ]] | ||
Due to the so called | Due to the so called chemical shift, it is possible to get information about the chemical state of the probed atoms. | ||
The core electrons of the atoms are affected, meaning that the binding energy of the electrons are slightly shifted, when an atom is bonded to atoms of other elements. | The core electrons of the atoms are affected, meaning that the binding energy of the electrons are slightly shifted, when an atom is bonded to atoms of other elements. | ||
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The figure to the left gives an illustration of the effect. An XPS Si2p spectrum of a Si reference sample and a Si sample that was treated in HF shortly before the measurement, is clearly showing two different curves. The untreated spectrum has a clear feature at about 103 eV due to Si atoms bonded to oxygen. In the spectrum from the HF treated sample, only the feature steaming from Si-Si interaction is present. Note that both curves only shows the Si signal, but with an clear indication of the chemical state of the Si atoms in the samples. | The figure to the left gives an illustration of the effect. An XPS Si2p spectrum of a Si reference sample and a Si sample that was treated in HF shortly before the measurement, is clearly showing two different curves. The untreated spectrum has a clear feature at about 103 eV due to Si atoms bonded to oxygen. In the spectrum from the HF treated sample, only the feature steaming from Si-Si interaction is present. Note that both curves only shows the Si signal, but with an clear indication of the chemical state of the Si atoms in the samples. | ||
If you study polymers, you can detect the | If you study polymers, you can detect the presense of different chemical groups, for example (C-C),(C-OH),(C=O),(CF3) or (CF2-CH2) in the polymeric layer. And after surface treatments, you may examine differences in the polymeric layer. | ||
Note that binding energies for different chemical states often can be found in the | Note that binding energies for different chemical states often can be found in the literature. | ||