Features of the Course of the Solid-State Reactions in a Sn/Fe/Cu Trilayer Film System

Study of the mechanisms of the solid-state reactions in Sn/Fe/Cu thin films is interesting both from a fundamental point of view and from a view of the importance of emerging intermetallics in the technology of solder joints and thin-film lithium-ion batteries. By the integrated approach, including both X-ray phase analysis and local elemental analysis of the cross-sections of the films, the phase composition and the mutual arrangement of phases were studied, at various stages of the solid-state reaction occurring at different temperatures. The observed sequence of the appearing phases differs significantly from the expected one if the mass transfer took place by a volume diffusion through the forming layers.