Algorithm for evaluating layer thickness based on electron average energy shift analysis

Layer thickness estimation method using the average energy shift of electrons passing through the layer is presented. The traditional approach of analyzing the signal electron is extended by using the spectral distribution of the energy shift of the electrons. In this approach, the tendency of the multiple inelastic scattering spectra to increase the average energy shift, depending on the number of inelastic interactions, is utilized to estimate the thickness of a layer. An algorithm that uses this spectral energy shift to evaluate the layer thickness was developed and validated against calculated spectrum from a known materials and thicknesses. The thickness evaluation by this algorithm is in a good agreement with the known thickness.