Influence of preliminary ion bombardment on the formation of Co and CoSi$_2$ nanofilms on Si surface during solid-phase deposition

In this work, to obtain ordered nanophases of Co and CoSi$_2$, nuclei are preliminarily created on the Si surface by bombardment with Ar$^+$ ions with $E_0$ = 0.5 keV and $D$ = 8 $\cdot$ 10$^{13}$ cm$^{-2}$. It was found that a narrow band gap ($E_g\approx$ 0.3 eV) appears in the band structure at the Co layer thickness of less than 3 ML. The metallic properties of the Co film manifest themselves at a thickness of more than 4–5 ML. Heating the Co/Si(111) system at $T$ = 900 K leads to the formation of nanophases and CoSi$_2$ nanofilms. The $E_g$ value is 0.8 eV for the CoSi$_2$ nanophases with $\theta\approx$ 3 ML and 0.6 eV for the CoSi$_2$ film.