Kinetics of titanium silicide formation on single-crystal Si: Experiment and modeling

Abstract

The growth kinetics of titanium silicide grown from thin-film Ti-on-Si(100) and Si(111) reaction couples are investigated using primarily Auger electron spectroscopy. A Ti/precursor-phase/TiSi2/Si layered structure is found. The growth law of TiSi2 depends on substrate orientation. An activation enthalpy of ΔH=2.5–2.6±0.25 eV/atom, substantially higher than previously reported values, is determined. The total silicide growth (TiSi2+precursor) has nearly a parabolic time dependence implying that the precursor phase forms as ‘‘At1/2−Bt’’ using Si(111) as a substrate. A model based on mass diffusion from a moving interface is presented and is shown to be in good agreement with the experimental results. This model, which is used to determine the diffusion coefficient of Si in the precursor phase, can be applied to other similar binary compound systems containing line compounds.