X-RAY PHOTOELECTRON-SPECTROSCOPY AND SCANNING ELECTRON-MICROSCOPY OF BETA-FESI2 FILMS GROWN BY ION-BEAM-ASSISTED DEPOSITION

This paper reports the investigation of polycrystalline beta-FeSi2 films grown by Ion Beam Assisted Deposition (IBAD), performed by using a broad Ar+ beam bombarding (001) Si substrates during the evaporation of Fe atoms. Several energies (200-650 eV) and current densities (10-70 muA cm-2) have been used for the Ar+ beam, keeping the Fe evaporation rate at about 0.08 nm s-1. The formation of the silicide was achieved by in situ thermal annealing at T = 600-degrees-C, performed during or after the deposition process. Rutherford Backscattering Spectroscopy (RBS), Scanning Electron Microscopy (SEM) and X-Ray Photoelectron Spectroscopy (XPS) have been used to study the stoichiometry, the morphology and the chemical status of several samples obtained using different ion beam parameters. Strong morphological improvements, such as smoothing and pinhole closing, are observed for the IBAD films grown during thermal annealing. The XPS depth profiling technique has been used to investigate the morphology of the silicide/Si interface.