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 oC 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 oC 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.