Nb-Ge-C nanocomposite thin films were deposited by dc magnetron sputtering using three elemental targets. The films consist of substoichiometric NbCx in a nanometer-thick matrix of amorphous C and Ge. Films with no Ge contain grains that are elongated in the growth direction with a (111) preferred crystallographic orientation. With the addition of ∼12 at. % Ge, the grains are more equiaxed and exhibit a more random orientation. At even higher Ge contents, the structure also becomes denser. The porous structure of the low Ge content films result in O uptake from the ambient. With higher C content in the films both the amount of amorphous C and C/Nb-ratio increases. The contact resistance was measured by four-point technique as a function of contact force between 0 and 10 N. The lowest contact resistance (1.7 mΩ) is obtained at 10 N. The resistivity varies between 470 and 1700 μΩ·cm depending on porosity and O content.
Structure and electrical properties of Nb-Ge-C nanocomposite coatings
Olof Tengstrand, Nils Nedfors, Lars Fast, Axel Flink, Ulf Jansson, Per Eklund, Lars Hultman; Structure and electrical properties of Nb-Ge-C nanocomposite coatings. J. Vac. Sci. Technol. A 1 July 2014; 32 (4): 041509. https://doi.org/10.1116/1.4882856
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