X-ray photoelectron spectroscopy of SPE-grown bcc-Fe, polycrystal and β-FeSi2 phases on Si(111) surfaces

摘要

Ultrathin films of iron silicides were grown on Si(111) surfaces by solid phase epitaxy (SPE); iron deposition and subsequent annealing, and analyzed using in situ high energy-resolution X-ray ph otoelectron spectroscopy (XPS).We analyzed peaks using Lorentzian andDonaich- ˇSunji′c curves and estimated the validity of both fittings. Under the sequence from bcc-Fe to polycrystal phase (the mixture of Fe3Si and β-FeSi2), and then β-FeSi2 phase with annealing process, the slight chemical shifts of Fe 2p3/2 toward higher binding energy (BE) and the reduction of peak asymmetry for Fe 2p3/2 and Fe 2p1/2 were observed.We attributed this behavior to the reduction of themetallicity in iron silicide films.