Isothermal phase transformation kinetics in stoichiometric GeSbTe thin films

The purpose of this work is to investigate the isothermal phase transformation in thin films of Ge 2 Sb 2 Te 5 and Ge 1 Sb 2 Te 4 alloys. From experimental and computed simulations it was shown that if the kinetic behavior is interpreted employing the Johnson-Avrami-Mehl-Kolmogorov theory, three slopes can be observed: the first related to a metastable transformation, the second to the step between metastable and stable transformation, and the last to the stable phase nucleation and growth. From X-ray patterns it was found that a metastable phase, which appears during the beginning of crystallization for Ge 2 Sb 2 Te 5 and Ge 1 Sb 2 Te 4 thin films. corresponds to the Ge 1 Sb 4 Te 7 fcc composition.