Specific Process Knowledge/Characterization/XPS/XPS technique: Difference between revisions
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There are two reasons why the technique is extremely useful: | There are two reasons why the technique is extremely useful: | ||
* The kinetic energy of the photoelectrons may be determined with such high accuracy (for instance, the resolution of the spectrometer is roughly 1 eV compared to the ~130 eV resolution of the spectrometer in an EDX X-ray detector ) that the small changes in binding energy of the sample electrons caused by the binding to other atoms may be detected. It is therefore possible to see if elements are present as oxides, nitrides etc. | * '''Chemical sensitivity:''' The kinetic energy of the photoelectrons may be determined with such high accuracy (for instance, the resolution of the spectrometer is roughly 1 eV compared to the ~130 eV resolution of the spectrometer in an EDX X-ray detector ) that the small changes in binding energy of the sample electrons caused by the binding to other atoms may be detected. It is therefore possible to see if elements are present as oxides, nitrides etc. | ||
* The inelastic mean free path of the photoelectrons is very short - as a result, photoelectrons from depths larger than some 10 monolayers will not contribute to the peaks as they have lost part of their kinetic energy. | * '''Surface sensitivity:''' The inelastic mean free path of the photoelectrons is very short - as a result, photoelectrons from depths larger than some 10 monolayers will not contribute to the peaks as they have lost part of their kinetic energy. | ||
The basic principle is shown below (the image is taken from Wikipedia). | The basic principle is shown below (the image is taken from Wikipedia). | ||