Ni/Cr interface width dependence on sputtered depth

Abstract

The composition depth distribution of an interface as determined by Auger sputter depth profiling is dependent, to a large extent, on both the ion-bombardment-induced cascade mixing and on the surface topography generated as a result of ion erosion. We assess the relative influence of these two processes on the depth resolution by comparing interface widths obtained by Auger sputter depth profiling (resulting from both the cascade mixing and the topography) to interface widths obtained by computer simulation (due to cascade mixing alone). Depth profiles were measured at eight successive interfaces of a multilayered Ni/Cr/Ni/Cr ⋅⋅⋅ thin-film structure using both 1- and 3-keV argon ion beams for sputter profiling. These interface widths increase with sputter depth, the increase being more rapid for the 3-keV bombardment. The calculations with the computer code evolve contain modeling of all contributions to interface broadening, except that of surface topography, thus resulting in constant values of interface widths. The difference in width obtained from the measured and calculated data is used to estimate the extent of the topography produced as a function of sputtered depth.