Structural analysis of co-sputtered Cu-Nb and Cu-Pd textured thin films
Structural characterization of nanoscale-two-metal-phase systems, which exhibit partial, complete, or no mixing when co-sputtered with a few percent of a minority element, is extremely challenging. Co-sputtering two metals at room temperature results in frozen disorder within the deposited films. Distinguishing the contribution of each metal phase, determining the distribution and self-organization of the second constituent element within the lattice, accurately quantifying the extra element content, and assessing internal disorder through diffraction analysis are complex and require the development of a suitable model to fit diffraction patterns from various geometries. Here, we present a model to describe the structural distribution of alloy elements in magnetron-sputtered Cu thin films, exploring two contrasting cases: 1) with the mutually immiscible Nb and 2) with Pd, which has a negative heat of mixing with Cu, forming stable alloys. A comparison between X-ray diffraction data and energy-dispersive X-ray spectroscopy-derived elemental distribution is discussed.