Rhodium and silicon system: I. Glassy metallic alloy formation

Abstract

Detailed characterizations of rhodium/silicon films prepared by co-deposition usingmagnetron sputtering have been carried out on silicon substrates at room temperature.Effects of the silicon content incorporated in the film on the chemical bonding state andcrystallinity were investigated using XPS/UPS, XRD and SEM. It should beemphasized that XPS/UPS measurements are carried out without breaking the vacuumto avoid any contamination of the film. All x-ray diffraction patterns revealeda high degree of amorphization. There is only a weak Rh pattern and a weakRh2Si pattern for 20 and 37 at.% of Si, respectively, i.e. showing a formation of glassy metallicalloy. A negative shift in the Rh core level binding energy for rhodium-rich alloys is mainlyreferred to relaxation effects due to a high density of d-states near the Fermi level.The filling of the d-states is completed between 25 and 40 atomic concentrationof Si. Valence orbital transformation due to the Si–Rh interactions is causingthe progressive positive shift in the binding energy for higher silicon content.