engleski

Crystallization kinetics of amorphous AlxMo1-x thin films under isochronal conditions

Phase transformation and crystallization kinetics of the AlxMo1􀀀 x (30  x  85) amor- phous thin lms under isochronal conditions was examined by continuous in situ elec- trical resistance measurements in vacuum. The sample preparation was performed by magnetron codeposition in the CMS 18 sputtering system at room temperature. For the purpose of examination of thermal stability and crystallization kinetics the sam- ples were deposited onto alumina ceramics. The structure of the as-deposited lms was examined by the XRD. The absolute value of corresponding temperature coecient of the resistivity (TCR), , increased with the aluminum content up to 􀀀 13:010􀀀 4 K􀀀 1 for Al75Mo25. Values of  and are in accordance with the Mooij correlation, and re ect typical properties of the amorphous alloys containing early transition metals. The samples were radiatively heated with a heating rate from 2 to 8 K/min. The activation energy for crystallization and the reaction order were determined within the framework of the JMA theory adopted for non{;isothermal kinetics. For the calculation of the Avrami exponent, independent of the activation energy results, we employed the method originally proposed by Ozawa, and for the amorphous Al75Mo25 n is  2 ; 0. Activation energy for the same composition is Ea  1 ; 4 eV. The results indicated that the crystallization mechanism in isochronal heating was a di usion{;controlled process with quenched{;in nucleus.

crystallization; amorphous; aluminum; molybdenum; thin films

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