Grazing incident X-ray fluorescence combined with X-ray reflectometry metrology protocol of telluride-based films using in-lab and synchrotron instruments
Résumé
Telluride films are widely applied in data storage devices (advanced resistive memories, DVDs and Blue-rays disks), photovoltaic cells and infrared detectors. The properties of thin telluride alloys are deeply influenced by their chemical composition and compositional depth profile, whereas surface/interface effects may become preponderant in ultrathin films. The combination of X-ray reflectometry (XRR) and grazing-incidence X-ray fluorescence (GIXRF) is particularly adequate to probe these complex thin layered materials.
In this paper, we evaluate the performances of Lab-based and synchrotron-based XRR/GIXRF strategies to characterize ultrathin (<10 nm) amorphous titanium‑tellurium films elaborated by Physical Vapor Deposition (PVD), and capped in situ with 5 nm‑tantalum passivation layer. We highlighted the impact of the instrumental setup on the qualitative XRR and GIXRF data and on the quantitative information deduced from the combined analysis. Both synchrotron-based and Lab-based strategies were sensitive enough to track the impact of small PVD process changes on the chemical depth-profiles, and to unambiguously reveal undesired tantalum‑tellurium inter-diffusion that was confirmed by X-Ray Photoelectron Spectroscopy.