Interface Width Dependence on Sample Temperature During Auger Sputter Depth Profiling of Cr/Ni Multilayered Thin Films

A NIST standard reference material (SRM 2135) composed of nine alternating Cr and Ni thin-film layers has been sputter profiled using 1 keV Ar ions both at room temperature and at elevated temperature. Interface widths of the Cr-to-Ni and Ni-to-Cr interfaces were monitored using Auger electron spectroscopy. At temperatures ranging from 400-700K, a very pronounced broadening was observed at each of the Cr-to-Ni interfaces. At these elevated temperatures, changes in the widths of the Ni-to-Cr interfaces, however, were slightly less. When previously heated specimens were again profiled at room temperature, the interface widths obtained were virtually unchanged from those measured before heating. It is concluded that temperature-assisted radiation enhanced diffusion is occurring during the sputter profiling process at elevated temperatures.