ENTROPIC ORIGIN OF THE FREE-ENERGY BARRIER TO NUCLEATION OF CRYSTALLITES IN AMORPHOUS COSI2 THIN-FILMS

The temperature dependence of the free energy barrier to nucleation of cobalt disilicide crystallites in amorphous CoSi2 thin films is determined based on a newly developed model-independent method. Contrary to prevalent views, we found that the free energy barrier to nucleation of cobalt disilicide crystallites is dominated by the entropic barrier, and the nucleation enthalpic barrier is relatively small. The results suggest that the nucleation of CoSi2 crystallites is essentially a process of topological rearrangement of the amorphous disordered structure into an ordered structure. © 1995 The American Physical Society.