Magnetron-sputter epitaxy of β-FeSi2(220)/Si(111) and β-FeSi2(431)/Si(001) thin films at elevated temperatures

beta-FeSi2 thin films have been grown on Si(111) and Si(001) substrates by magnetron-sputter epitaxy at 700 degrees C. On Si(111), the growth is consistent with the commonly observed orientation of [001]beta-FeSi2(220)//[1-10]Si(111) having three variants, in-plane rotated 120 degrees with respect to one another. However, on Si(001), under the same growth conditions, the growth is dominated by [-111]beta-FeSi2(431)//[110]Si(001) with four variants, which is hitherto unknown for growing beta-FeSi2. Photoelectron spectra reveal negligible differences in the valance-band and Fe2p core-level between beta-FeSi2 grown on Si(111) and Si(001) but an apparent increased Si-oxidization on the surface of beta-FeSi2/Si(001). This phenomenon is discussed and attributed to the Si-surface termination effect, which also suggests that the Si/Fe ratio on the surface of beta-FeSi2(431)/Si(001) is larger than that on the surface of beta-FeSi2(220)/Si(111). (C) 2012 American Vacuum Society. [http://dx.doi.org/10.1116/1.4731200]