Scanning Microscopy


A principal step in the extraction of Auger electron yields and line shapes from electron-excited spectra is an understanding of the attendant electron background. Experiments are reported here in which the influence of the primary electron beam angle of incidence on Auger spectral backgrounds has been separated from that of the angle of electron emission. The secondary electron background for clean polycrystalline palladium, on the high-energy side of the MNN peaks, have been studied as functions of primary beam angle of incidence and beam energy. For the range of beam energies investigated, < 10 keV, linearization of the secondary cascade is easily observed in log-log plots of intensity versus energy. When cascades are fitted with Sickafus-type functions, AE-m (E = electron energy), the parameter m is found to depend on the beam angle of incidence but not on the beam energy. The effect of increasing primary beam energy is to enlarge the energy interval over which linearization can be observed. The low-energy inelastic "step" or "tail" accompanying the background-subtracted Auger peaks grows in intensity as the angle of incidence approaches that of the surface normal.

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