CRYSTALLIZATION OF AMORPHOUS COSI2 THIN-FILMS .1. KINETICS OF NUCLEATION AND GROWTH

The kinetics of nucleation and growth of spherulites in amorphous CoSi 2 thin films of 100 nm of thickness have been studied in situ by trans mission electron microscopy. The time dependence of the number of nucl ei showed pronounced transient character. The growth rate was found to be constant upon isothermal annealing in the temperature range of 130 to 170-degrees-C in a broad interval of time. The activation energy o f incorporation of growth units into the crystal lattice was found to be 23.9 kcal/mole. For the surface free energy between the crystallite s and the amorphous phase the value 212 erg/cm2 has been determined fr om the nucleation experiments. The nucleation was found to occur rando mly in the bulk of the amorphous film with a constant rate during the transformation process as deduced from the average value n = 3.8 in th e Avrami kinetic law for overall crystallization xi = 1-exp(-kt(n)).