Effect of the linewidth reduction on the characteristic time spread in C49-C54 phase transition

The kinetics of the C49-C54 phase transformation in TiSi2 narrow strips for width in the 0.5-1.3 OEºm range was investigated by sheet resistance measurements. The experimental data follow the Johnson-Mehl-Avrami equation for the fraction of the transformed material, with an exponent equal to 1 for all of the analyzed linewidths. Nucleation sites saturation occurs and the growth is one-dimensional along the length of the strip. The characteristic time, as obtained by the fit, increases as 1/W, W being the width of the strip, and a nucleation density of about 0.05 sites/OEºm2 has been obtained. The distribution of the characteristic times around the average value increases with decreasing the linewidth. The amplitude of the dispersion is in quantitative agreement with the statistical fluctuation of the number of nucleation sites. ¬© 1998 American Institute of Physics.