Microstructure and properties of nanocrystalline Cu-Nb thin films prepared by unbalanced magnetron sputtering ion plating

doi:10.13251/j.issn.0254-6051.2021.12.025

Abstract

Abstract: Influence of Nb content on microstructure and properties of the nanocrystalline Cu-Nb film was studied. The Cu-Nb nanocrystalline films with different Nb content were prepared on single crystal Si substrate with (100) crystal plane and glass substrate by unbalanced magnetron sputtering ion plating technology, and the effect of Nb content on their microstructure and properties was studied. The specimens were annealed at 400 ℃ in a horizontal vacuum annealing furnace. The microstructure, mechanical properties and electrical properties of the films before and after annealing were analyzed by using a field emission scanning electron microscope equipped with energy dispersive X-ray spectrometer, atomic force microscope, X-ray diffraction and nanoindenter and four-probe resistivity tester. The results show that the as-deposited Cu-Nb film surface is composed of dense nanocrystallines without obvious defects such as holes and cracks, and with the highest surface roughness of only 8.54 nm. With the increase of Nb content, the average grain size of the film is decreased by 5 nm. The hardness of the film is also increased due to fine-grain strengthening, which showing a maximum value of 4.9 GPa with a Nb target current of 1.3 A. Compared with the as-deposited specimen, the as-annealed specimen has a little changes in hardness, elastic modulus, average grain size and surface roughness, which indicates that the as-annealed Cu-Nb film exhibits excellent thermal stability. The addition of Nb can effectively refine the grains and increase the hardness of the film. At the same time, the immiscibility of Cu-Nb allows the nanocrystalline film to maintain better thermal stability at high temperatures. When the sputtering current of Nb target is 0.5 A, the performance of the Cu-Nb film is the best: for the as-deposited Cu-Nb the resistivity is the lowest of 3.798×10^-7 Ω/m, the film thickness is 1050 nm, the roughness is 4.70 nm, and the hardness and elastic modulus are as high as 4.6 GPa and 139.5 GPa, respectively.

Key words: unbalanced magnetron sputtering, nanocrystalline Cu-Nb thin film, electrical and mechanical properties, thermal stability

CLC Number:

TB43

Wang Yupeng, Wu Hongjun, Bao Mingdong, Tian Wu, Zhou Bing. Microstructure and properties of nanocrystalline Cu-Nb thin films prepared by unbalanced magnetron sputtering ion plating[J]. Heat Treatment of Metals, 2021, 46(12): 156-161.

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