Growth of β-FeSi2 films via noble-gas ion-beam mixing of Fe/Si bilayers

TLDR: A detailed study of the formation of β-FeSi2 films by ion-beam mixing of Fe/Si bilayers with noble gas ions is presented in this paper, where the structures were analyzed by Rutherford backscattering spectroscopy, x-ray diffraction, conversion electron Mossbauer spectrograph, elastic recoil detection analysis, cross-section high resolution transmission electron microscopy, and energy dispersive x-rays spectroscope.

Abstract: A detailed study of the formation of β-FeSi2 films by ion-beam mixing of Fe/Si bilayers with noble gas ions is presented. Fe films of 35–50 nm deposited on Si (100) were irradiated with 80–700 keV Ar, Kr, or Xe ions in a wide temperature interval, from room temperature to 600 °C. The structures were analyzed by Rutherford backscattering spectroscopy, x-ray diffraction, conversion electron Mossbauer spectroscopy, elastic recoil detection analysis, cross-section high resolution transmission electron microscopy, and energy dispersive x-ray spectroscopy. Already after Xe irradiation at 300 °C the whole Fe layer is transformed to a mixture of Fe3Si, e-FeSi, and β-FeSi2 phases. At 400–450 °C, a unique, layer by layer growth of β-FeSi2 starting from the surface was found. A full transformation of 35 nm Fe on Si to a 105 nm β-FeSi2 layer was achieved by irradiation with 205 keV Xe to 2×1016 ions/cm2, at a temperature of 600 °C. The fully ion-beam grown layers exhibit a pronounced surface roughness, but a sharp in...