Interfacial properties and characterization of Sc/Si multilayers

We investigate the intermixing of layers in Sc/Si and Sc/B4C/Si/B4C multilayers using electron and synchrotron excited soft X-ray emission and absorption spectroscopy. The multilayers are annealed at 100, 200, 300, 400 and 500 °C after preparation by magnetron sputtering. Silicon Kβ emission and reflectivity measurements verify that the non-annealed multilayer systems are composed of distinct layers with only a minor interdiffusion in Sc/Si samples whereas annealing Sc/Si multilayers at 400 °C leads to a degradation of the multilayer structure and the formation of intermittent scandium silicide, ScSi. The presence of B4C barriers in Sc/B4C/Si/B4C hinders this degradation from developing for the entire temperature range considered. The barrier layers continue to be effective for the entire temperature range even after an extended shelf-life.