Rhodium and silicon system: I. Glassy metallic alloy formation

Detailed characterizations of rhodium/silicon films prepared by co-deposition using magnetron 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 and crystallinity were investigated using XPS/UPS, XRD and SEM. It should be emphasized that XPS/UPS measurements are carried out without breaking the vacuum to avoid any contamination of the film. All x-ray diffraction patterns revealed a high degree of amorphization. There is only a weak Rh pattern and a weak Rh(2)Si pattern for 20 and 37 at.% of Si, respectively, i.e. showing a formation of glassy metallic alloy. A negative shift in the Rh core level binding energy for rhodium-rich alloys is mainly referred 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 concentration of Si. Valence orbital transformation due to the Si-Rh interactions is causing the progressive positive shift in the binding energy for higher silicon content.