engleski

Crystallization behaviour of Al-W amorphous thin films

The Al-W thin films, with composition in the range from Al80W20 to Al66W34, were prepared by simultaneous d.c. sputtering of both aluminium and pure tungsten (on glass, fused quartz, alumina or sapphire as substrates) in a multiple source sputtering apparatus. The prepared films was investigated by XRD using a Philips PW 1820 vertical goniometer with monochromatized Cu Ka radiation and by measuring electrical resistivity. Thin films were found completely amorphous and the negative temperature coefficient of the electrical resistivity confirmed the amorphous state. Thermal stability of amorphous films deposited on fused quartz was investigated by isothermal annealing procedure. It was found that amorphous films did not crystallize up to 400 C. However, at 500 C and higher temperatures, the W2Si phase and some unidentified lines were detected on XRD patterns on films deposited on quartz substrate, showing the reaction of films with substrate. As-deposited films on alumina substrates were also amorphous and stable up to 500 C. Investigation of the crystallization behaviour of the amorphous films, using annealing procedure on temperatures between 530 C and 690 C, are now in progress. The results will be available at the time of Conference.

Amorphous Thin Films; XRD; Al-W; codeposition

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