EPITAXY ENHANCEMENT OF BETA-FESI2 GROWN BY ION-BEAM ASSISTED DEPOSITION

Iron silicide layers have been grown by 200 eV Ar+ beam assisted deposition of Fe onto [001] Si single crystals maintained at high temperatures. Polycrystalline FeSi has been formed at T=400-degrees-C while partially epitaxial beta-FeSi2 was obtained after deposition at 500-degrees-C. Samples have been analyzed by Rutherford backscattering spectroscopy and transmission electron microscopy. The main effects of the ion beam have been the reduction of the average grain size of the polycrystallites for both phases and the enhancement of the epitaxial fraction for the beta-FeSi2 phase. The role of the ion beam during the formation of the iron silicides has been discussed.