Fabrication of iron disilicide from multilayer by helicon plasma sputtering
(1.College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China2.Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, M5S 1A4, Canada)
Abstract: Helicon plasma sputtering of Fe/Si multilayer followed by thermal annealing in Ar atmosphere was used to fabricate β-FeSi2 films. [Fe 0.5nm/Si 1.6nm] 120 multilayer was deposited on Si（100） substrate and then the samples were annealed at 900℃ for 2h or at 9001000℃ for 10s. Annealed samples were characterized by X-ray diffractometry（XRD）, Rutherford backscattering spectroscopy, scanning electron microscopy and optical absorption measurement. （202）/（220） oriented β-FeSi2 films are fabricated from the multilayer according to XRD patterns. It is found that there is a very small redistribution of Fe and Si components in the films during the thermal annealing, so that a good stoichiometry of FeSi2 can be obtained. It is also revealed by scanning electron microscopy that multilayer technology can result in a smooth surface for β-FeSi2 films. Optical absorption spectra demonstrate that the films have a direct band gap of 0.9eV at room temperature.
Key words: iron disilicide； sputtering； multilayer； thermal annealing