Reconstruction of the depth profile from angle‐resolved AES/XPS

The effects of elastic scattering on the information available from angle‐resolved electron spectroscopies on noncrystalline materials is studied. These effects force the consideration of elastic scattering cross‐sections which are dependent on atomic concentration and therefore on depth. This is done by discretizing the transport equation within a two‐stream/transport approximation. The variation of inelastic mean free paths with composition is also included. It is also pointed out that, in addition to the ill‐conditioning problems and the possible numerical non‐uniqueness, the inversion of the Laplace transform required for reconstruction of the depth profile introduces a second analytical non‐uniqueness. It is suggested that the reconstruction of the depth profile should be performed using a highenergy peak to obtain an approximate depth profile (large inelastic mean free path, high depth penetration) and that the full quantification should be performed on a low‐energy peak (small inelastic mean free path, low depth penetration).