Peak intensities in Auger electron spectroscopy for quantification: Relationship between differentiated spectral intensities and direct peak areas

In Auger electron spectroscopy, qualitative analyses are performed by using high-energy resolution direct spectra with a spherical capacitor analyzer (SCA). Although it is used to carry out quantitative analyses with differentiated spectra, high-energy resolution spectra measured with an SCA differ from those obtained with conventional energy resolution measurements using a cylindrical mirror analyzer. When we attempt quantitative analyses by applying direct spectra, this does not allow the use of previously accumulated analytical parameters for differentiated spectra, such as relative sensitivity factors. Therefore, we clarified the relationship between Auger direct spectral intensities and differentiated spectral intensities, and we defined a correction factor enabling the use of the analytical parameters given by differentiated spectra to direct spectra. To estimate the direct spectral area contributing to a quantitative analysis, the background of the direct spectrum is subtracted by the Shirley method, similar to the spectral treatment used in x-ray photoelectron spectroscopy. The correction factor is expressed as the ratio of the normalized peak area and normalized differentiated peak-to-peak intensity, which is actually measured and determined in every laboratory and with any instrument.