INVESTIGATE THE APPROPRIATE MODEL FOR DESCRIBING THE CRYSTALLIZATION PROCESS OF Te65Sb25Ga10 THIN FILM

Abstract

The sheet resistance, Rs , measurements versus temperature, T, for 1000 nm Te - Sb -Ga thin films were performed at different heating rates (   5, 10, 20, 30 and 40 K/min) in the temperature range from 300 to 673 K. The kinetic transformation parameters of Te65Sb25Ga10 thin film were examined via the theoretical method developed (TMD) and the Johnson–Mehl–Avrami model (JMA). The crystallization activation energy Ec with the transformed fraction is not constant but change with the conversion fraction. These results refer to the rate constant of the transformation is in fact determined through the nucleation and diffusion processes. The results of the impingement exponent γi dependence of the conversion fraction (χ) revealed that the mode of impingement is due to “anisotropic growth”. In addition to that the average values of kinetic exponent parameters, n and m obtained by (TMD) and JMA models. are accounted for two and three-dimensional crystal growth with heterogeneous nucleation. Moreover, comparing the experimental curve of the transformed fraction indicated that the crystallization process of Te65Sb25Ga10 thin film cannot be satisfactorily described by Johnson-Mehl-Avrami (JMA) model. On contrary, the theoretical curves of the developed model are more realistic for describing the crystallization process of the investigated chalcogenide bulk glass.