Silicide formation at HfO2-Si and ZrO2-Si interfaces induced by Ar+ ion bombardment

The effect of ion bombardment with Ar+ at several keV energy ranges resulting in silicide formation at HfO2-Si and ZrO2-Si interfaces has been investigated in situ with x-ray photoelectron spectroscopy. The set of spectra recorded during the growth of thin HfO2 and ZrO2 layers on Si(100) was compared to those obtained during subsequent sputtering with an Ar+ beam. It is shown that the Ar+ ion beam affects the MeO2-Si (Me=Hf,Zr) interface at thickness ≤3 nm, inducing the formation of a silicide layer ∼2 nm in thickness. The proposed mechanism of silicide formation including the depletion of the interface in oxygen due to its preferential sputtering and subsequent Hf-Si intermixing is corroborated by computer simulations