Influence of defects on the kinetic of C49-C54TiSi(2) transformation

TiSi2 C49 thin films with different concentrations of defects have been prepared by conventional annealing, in the 460-540 degreesC temperature range, of a Ti films deposited on a polycrystalline Si layer. The residual sheet resistance of the C49 films decreased with increasing both the annealing temperature and the annealing duration indicating the occurrence of defect annealing at higher temperature and/or longer times. A successive annealing at 650 degreesC was used to promote the C49-C54 transition and the transformation rate was measured by in situ sheet resistance measurements. The C49-C54 transition time decreased with the residual sheet resistance of the C49 phase. The activation energy for the transformation increased from 3.09+/-0.75 to 6.12+/-0.96 eV with increasing the defect concentration in the C49 phase. This strong dependence can explain the large variation of the kinetic results reported in the literature.