ESTIMATION OF EXCITATION DEPTH DISTRIBUTION FROM ELECTRON-EXCITED AUGER-SPECTRA OF IRON USING PEAK SHAPE-ANALYSIS

We have studied the dependence of the Auger peak shape on primary elec tron energy for polycrystalline iron and have succeeded in extracting information about the excitation depth distribution. Iron LMM spectra were measured with different incident primary energies (1.25-4.00 keV) and the reflection electron energy-loss spectroscopy (REELS) spectrum was measured at an energy of 0.7 keV corresponding to the average Fe LMM Auger energy. In the inelastic background analysis, we approximate d the depth distribution function f(x) of emitting atoms as a rectangu lar or an exponential decay model. Using the inelastic scattering cros s-section from REELS, the analysis separated the spectra into the intr insic Anger spectra and the inelastic peak backgrounds corresponding t o the f(x) at each incident energy. It was found that the exponential model was a more suitable model for f(x) than the rectangular model. T he exponential decay length of excitation; for Anger electrons was fou nd to increase significantly as the primary energy increased.