engleski

PHASE TRANSFORMATION OF AMORPHOUS Al78W22 THIN FILMS UNDER ISOTHERMAL CONDITIONS

Partial phase transformation of the amorphous Al78W22 thin films under isothermal conditions was examined by continuous in situ electrical resistance. The sample preparation was performed by magnetron codeposition. For preventing the nucleation mechanisms of crystallization, the substrates on which the films were deposited were cooled to the temperature of approximately 180 K. Influence of the relaxation processes upon the phase transformation investigation was avoid by isochronal pre-annealing at 790 K. The resistivity of the samples was monitored during isothermal annealing at 803, 813 and 823 K, respectively, i.e. at the temperatures where the crystalline phase starts to develop. The dependence of the resistance on the volume fraction of crystalline phase was established using a general two phase resistivity models for this system. The activation energy for crystallization and the reaction order were determined within the framework of the JMA theory. The analysis of the reaction order suggests that the nucleation is probably dominant mechanisms of crystallization.

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