RBS DEPTH PROFILING OF LIGHT-ELEMENTS IN NONHOMOGENOUS BINARY FILMS

Accurate determination of depth profiles of light elements in non-uniform samples by standard RBS (Rutherford backscattering) is a non-trivial task. Thin non-uniform film samples consisting of two elements with a large difference in atomic weight and situated on top of a substrate containing only the heavier element are considered. The depth profile of the lighter element distributed in the film is deduced from relevant parts of the RBS spectrum of the heavier element. An iterative procedure is suggested by which the light element depth distribution can be determined from RBS data with due regard to the composition variation with the depth. The performance of the procedure is demonstrated on samples comprising thin Si1-cNc films deposited by different techniques on Si substrate and oxidized tungsten.