Morphological, electrical, and electromagnetic characterization of nanometric films of Cu and Ni and their combination in bilayers

Abstract

Modern developments in telecommunication and microelectronics have resulted in spurious radiation, which can promote electromagnetic interference and environmental pollution. To minimize this problem, this work studied nanometric metallic films (65 nm/layer) based on Cu and Ni and their combinations in bilayers deposited on a polyethylene terephthalate substrate by magnetron sputtering. Field emission gun scanning electron microscopy analyses showed that the films have different morphological textures, due to the processing parameters and the free energy of the metals. Electrical measurements by the 4-point method and dielectric spectroscopy showed that the films have low conductivity values, due to oxides formed on the surfaces of the films and defects. X-ray diffraction confirmed the formation of metallic oxides in the films. Electromagnetic characterization (8.2-12.4 GHz) of the monolayer films showed poor performance. Meanwhile, the bilayer films (Ni/Cu and Cu/Ni) showed different behaviors with reflection and absorption contributions. Attenuation values close to 95 % for the Cu/Ni film were obtained.