Thin amorphous tantalum films are prepared on Si(111) substrates in a metallic glassy state. The amorphous monoatomic state of the film is characterized by X-ray diffraction studies. The glassy state leads to a negative temperature coefficient of the resistivity (TCR) for low sample temperatures <200 K which is attributed to incipient localization. Above 200 K a positive TCR is observed as expected for a normal Boltzmann transport regime. Upon heating the Si substrate to 1200 K TaSi2 is formed out of the amorphous tantalum film and the silicon substrate. The TaSi2 layer is crystalline as evident from X-ray diffraction data.
Schematic drawing of the evaporation setup on either glass or silicon samples. Scheme of annealing effects.
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