Low-energy Ar+ ion-beam induced vanadium silicide formation at V/Si interfaces

Vanadium/silicon interfaces produced by V thin film deposition on Si substrates were ion-beam mixed using 2 and 3 keV Ar+ ions at room temperature. The ion-beam mixing (IBM) has been studied by means of X-ray photoelectron spectroscopy, factor analysis and TRIDYN simulations. Comparison of the experimental results with those obtained from TRIDYN simulations suggests that, in addition to pure ballistic ion mixing mechanisms, other radiation-enhanced diffusion processes could contribute to the IBM of V/Si interfaces by low-energy Ar+ bombardment at room temperature. The kinetics of interface formation by IBM is characterized by two stages. During the first stage, a strong decrease of metallic V species is observed due not only to sputtering but also to the formation of vanadium silicide. The concentration of vanadium silicide related species reaches a maximum at the end of this first stage, decreasing subsequently. Finally, with increasing sputtering time, the signals associated with the silicide slowly decrease, and pure silicon species begin to appear, since no free metallic vanadium atoms are available to react with the unlimited silicon supply from the substrate.