AbstractThe compositional profile of an interlayer inferred from Fresnel contrast data is usually determined assuming that the variation in the measured mean forward scattering potential is associated with changes in neutral atom scattering factor and atomic density. However, the technique is currently being applied to systems for which the form and the magnitude of the potential at the layer can be affected strongly by changes in ionicity. Here, we show how the analysis of ‘delta-doped’ layers in semiconductors, which contain thin layers of impurity ions at low concentrations, requires the analysis of not only the effect of strains on the density but also the contribution to the potential from charged ions surrounded by a wider spread of free carriers.
