Structure of epitaxial gadolinium silicide thin films obtained by Gd evaporation and by Gd and Si coevaporation on Si(111)

Abstract 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 annealing at three different temperatures 400°C, 450°C, and 740°C for 15 minutes, these samples were analysed by Ultra Violet Electron Spectroscopy (UPS), X Ray Electron Spectroscopy (XPS), Secondary lon Mass Spectroscopy (SIMS), Low Energy Electron Diffraction (LEED), and Grazing Incident X Ray Diffraction (GIXRD). It was concluded that the silicide thin films obtained, approximatively 12 nm thick, verify a chemical formula Gd 3 Si 5 with “free” or cluster forming silicon embedded in films in concentrations which could be as high as 30%. Cristallographic structure is an hexagonal AlB 2 type one for samples annealed at temperatures higher than 400°C.