CEMS study of the interface formation in the Fe-Si system during pulsed laser deposition

摘要

The formation of Fe/Si and Si/Fe interface structures at room temperature during pulsed laser deposition of Fe on Si and Si on Fe, respectively, has been investigated by Fe-57 conversion electron Mossbauer spectroscopy (CEMS) utilising Fe-57 tracer layers. In both cases a layered structure is found consisting of a non-magnetic silicide interface phase and a solution of Si in alpha -Fe. The composition as well as the thickness of these interface layers change in the course of the deposition process. Their evolution is different for the two cases and depends on the deposited element and on its laser irradiance dependent energy, whereas the final silicide thickness remains remarkably constant (0.7-0.9 nm of Fe equivalent thickness). Implantation effects and a laser irradiance dependent silicide "sputtering" effect at the interface are shown to contribute substantially to the compositional changes and the irradiance dependence of the thickness of the phases, respectively, whereas the nature of the phases formed indicates a decisive role of thermodynamic forces in this non-equilibrium deposition process. [References: 32]