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Električna otpornost nepotpuno kristaliziranih AlW amorfnih slitina

Recently, thin films of amorphous-like tungsten were prepared by the CVD process. We present a preliminary characterization of the amorphous-like tungsten thin films prepared by magnetron sputtering. Thin tungsten films (approx. 0, 2 ? ; m) were prepared by magnetron sputtering of pure tungsten in a cylindrical magnetron device. Working gas pressure was varied in the range of 0, 7 � 3, 5 Pa, and substrates were cooled to LN2. Structure of the films was examined by the XRD and SAXS methods: films prepared at low argon pressure consist predominantly of stable ? ; -W phase, while the metastable ? ; -W prevails in films prepared at 2, 8 Pa argon pressure. The XRD-patterns of tungsten films deposited at 3, 5 Pa argon pressure regularly exhibit only a very broad signal centered at 2? ; ? ; 40? ; - a distinctive mark of amorphous metals and alloys. The grain size of such tungsten material was estimated from the width of this peak to be about 2 nm, which was confirmed by SAXS measurement. Thermal coefficient of the electric resistivity was negative � a characteristic feature of amorphous metals and alloys. Thus, thin tungsten films sputter-deposited onto cooled substrates at 3, 5 Pa argon pressure exhibit the amorphous-like structure. Thermal stability of the amorphous-like tungsten films was investigated by isochronal heating up to 720? ; C in vacuum, with continuous monitoring of electric resistivity. The electric resistivity drops sharply at about 300? ; C, and the XRD-analysis of the samples after a completed thermal cycle confirms a full transformation to the stable ? ; -W phase. The obtained results indicate that considerably thick films of amorphous-like tungsten can be prepared by magnetron sputtering, and that such material exhibits a considerable thermal stability.

W; amorfne slitine

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