Ellipsometric studies of adsorption reactions on clean surfaces

The ellipsometric effects measured upon adsorption in the monolayer range are discussed. In general there are two possible contributions, the effect of the adsorbed layer itself and the effect due to a change in the substrate surface induced by the adsorbed layer. The latter effect occurs mainly in the case of chemical adsorption.The ellipsometric measurements on a number of clean semiconductor surfaces are treated and the results are compared with those obtained by other methods, e.g. electron energy loss spectroscopy and ultra-violet photon spectroscopy.