Mechanical properties of Al-(Nb, Mo, Ta, W) thin films
Car, Tihomir1; Radic, Nikola1; Cekada, Miha2; Tonejc , Anton1
1Croatia;
2Slovenia

Thin films of AlxNb1-x (95 > x > 20), AlxMo1-x (90 > x > 20), AlxTa1-x (95 >x > 20), AlxW1-x (50> x > 80), has been prepared by magnetron codeposition in the CMS 18 sputtering system at room temperature. The structure of the as-deposited films was examined by the XRD, and the AlNb films was estimated amorphous in range from 30% to 85% aluminum content. Completely crystalline were Al95Nb5 and Al20Nb80 films. The AlMo films was estimated amorphous in range form 45% to 85% aluminum content, while completely crystalline were Al90Mo10 and Al40Mo60 samples. For the AlTa films amorphous range was from 40% to 85% aluminum content, and completely crystalline were Al95Ta5 and Al40Ta60 samples. The AlW films were found to be amorphous in range from 65% to 80% aluminum content, and completely crystalline were the Al60W40 and Al50W50 films. Beetwen regions of completely amorphous and crystalline films, for all combinations, there was a range of mixed crystalline and amorphous phase. The film thickness and stresses were measured by the Rank Taylor Hobson Form Talysurf. Average film thickness was from 325 to 400 nm, depending on the film composition. Stresses in AlMo and AlNb samples were tensile, while in AlTa films stresses were mainly compressive. Microhardness (load 2mN) was examined by Mitutoyo MVK-H2 device.
Microhardness of amorphous AlW and AlTa films was higher then bulk value of harder element (W, Ta) in combination. For AlNb i AlMo films microhardness is dominantly under influence of harder element and continuosly decreases with increasing of aluminum content. Part of the elastic energy in the microhardness values was roughly from 20% for AlMo to 60% for AlTa films.
back