Tilting angle dependence of Rutherford backscattering: uniformity of near surface layers

The angular dependence of MeV He+ backscattering yield in glancing geometry has been used to obtain experimental information on surface structure in thin films and implanted crystals. Uniform layer yields are characterized by the (cos phi)-1 dependence as a function of the target tilting angle phi. Deviations from this simple law found in annealed Pb layers deposited on Si substrate have been attributed to the shadowing effect produced by the hill-like structure observed also with SEM. (Auth.)