Reaction of the Si/Ta/Ti system: C40TiSi(2) phase formation and in situ kinetics

The effect of a thin Ta layer at the Si/Ti interface on the intermediate phase formation has been studied in detail by in situ sheet resistance, X-ray diffraction and transmission electron microscopy of partially reacted samples. When a Ta layer is deposited at the Si/Ti interface, a new intermediate phase has been detected, i.e., the hexagonal TiSi2 C40. This phase grows on the C40 TaSi2 that is formed at the interface with silicon. The activation energies of the C40 formation (1.9 +/-0.3 eV) and the C40-C54 phase transition (3.7 +/-0.5 eV) have been determined and compared to the activation energies for the C49 (1.7 +/-0.1 eV) formation and the C49-C54 (5.1 +/-0.9 eV) transition. Both the transformation kinetics and the film morphology are consistent with an increase of the nucleation density with respect to the C49-C54 transition. (C) 2002 American Institute of Physics.