INFORMATION DEPTH IN AUGER-ELECTRON SPECTROSCOPY

The depth from where the information comes in electron based spectroscopies is still a matter of controversy. In spite of having different physical meanings, inelastic mean free path, attenuation length, escape and information depths are parameters often taken as synonymous. In this work we analyze from the point of view of the Monte Carlo simulation the use of these parameters in Auger electron spectroscopy. We present results about the angular dependence of the electron yield, the in-depth contribution of the different layers to the total yield, and the electron energy and target mass dependence of the information depth. We found that the elastic scattering has two important effects on the electron transport: (i) the normal effect: the increase of the electron path inside the solid decreasing both the electron yield and the information depth, and (ii) the surface effect: the elastic scattering and the break of the isotropy of the medium due to the presence of a surface lowers the information depth, through the mechanism of increasing the electron yield coming from the near surface layers.