Backscattering-correction for AES spectra measured at oblique (>45°) incidence of primary electron beam

The validity of matrix corrections on an AES analysis for incident angles θ (measured from the surface normal) of >45° was examined. The correction factors to take into account were the atomic density correction factor (N), the electron backscattering correction factor (R) and the inelastic mean free path (λ). The backscattering correction factor at large incidence angles was estimated by extrapolation from the factors for θ < 45°, which have been reported based on Monte-Carlo simulations. The validity of the extrapolation was checked using pure Au and Cu samples used in the measurements of AES intensity dependence on the angle of incidence. This present approach then was applied to the quantitative analysis of Si₃N₄ samples for a large incident angles. It was confirmed that the proposed matrix correction method is more accurate than the conventional one based on the use of sensitivity factors.