STRUCTURE OF EPITAXIAL GADOLINIUM SILICIDE THIN-FILMS OBTAINED BY GD EVAPORATION AND BY GD AND SI COEVAPORATION ON SI(111)

Silicide thin films were epitaxially grown by Gd evaporation and by Si and Gd co-evaporation for 45 minutes on a Si (111) wafer. After annea ling at three different temperatures 400 degrees C, 450 degrees C, and 740 degrees C for 15 minutes, these samples were analysed by Ultra Vi olet Electron Spectroscopy (UPS), X Ray Electron Spectroscopy (XPS), S econdary ion Mass Spectroscopy (SIMS), Low Energy Electron Diffraction (LEED), and Grazing Incident X Ray Diffraction (GIXRD). It was conclu ded that the silicide thin films obtained, approximatively 12 nm thick , verify a chemical formula Gd3Si5 with ''free'' or cluster forming si licon embedded in films in concentrations which could be as high as 30 %. Cristallographic structure is an hexagonal AlB2 type one for sample s annealed at temperatures higher than 400 degrees C.