Effects of a Ta interlayer on the titanium silicide reaction: C40 formation and higher 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.