Effects of Ta interlayer on the titanium silicide reaction: C40 formation and scalability of the tisi2 process

When a Ta layer is deposited at the Si–Ti interface a new phase has been
detected, i.e., the TiSi2 C40. The C40–C54 transformation kinetics and the
film morphology are consistent with an increase of the nucleation density
with respect to the C49–C54 transition. The activation energies for the
nucleation rate (4.2±0.3 eV) and the growth velocity (4.0±0.4 eV) have been
obtained from the in situ sheet resistance and the transmission electron
microscopy results. These results show that the process with a Ta layer at
the Ti–Si interface has a greater scalability with respect to the standard
TiSi2 process.