Providing a Specified Level of Electromagnetic Shielding with Nickel Thin Films Formed by DC Magnetron Sputtering

Abstract

Nickel films of 4–250 nm thickness were produced by DC magnetron sputtering onto glass and silicon substrates. The electrical properties of the films were investigated by the four-probe method and the surface morphology of the films was studied by atomic force microscopy. To measure the shielding effectiveness, a portable closed stand based on horn antennas was used. A theoretical assessment of the shielding effectiveness of nickel films of various thickness under electromagnetic radiation of a range of frequencies was carried out using two different approximations. The results demonstrate the shielding effectiveness of up to 35 dB of the nickel thin films in the frequency range of 2–18 GHz.

Microstructure and Properties of Thin-Film Submicrostructures Obtained by Rapid Thermal Treatment of Nickel Films on Silicon

“…The nickel layers are used as orienting layers for growing graphene and copper films [2]. Thin nickel films are used as ohmic contacts [3] in the solar-to-thermal energy converters [1], as well as for electromagnetic radiation shielding [4].…”

“…Atomic force microscopy (AFM) is used more often to monitor changes in surface morphology, roughness [4,19,[21][22][23][24][25] and changes in grain size [4,21,22,25] when studying the nickel films on silicon (after annealing). AFM images are used to describe the smoothness [4,22], homogeneity and continuity [4] of the formed films.…”

“…Atomic force microscopy (AFM) is used more often to monitor changes in surface morphology, roughness [4,19,[21][22][23][24][25] and changes in grain size [4,21,22,25] when studying the nickel films on silicon (after annealing). AFM images are used to describe the smoothness [4,22], homogeneity and continuity [4] of the formed films. AFM is also used to verify the process of the film agglomeration during the transition from NiSi to NiSi 2 at temperatures from 500 • C when studying the structure, phase composition and resistivity [21].…”

“…AFM is also used to verify the process of the film agglomeration during the transition from NiSi to NiSi 2 at temperatures from 500 • C when studying the structure, phase composition and resistivity [21]. In this case, attention is focused on changes in morphology [19], the formation of a needle-like [23] or columnar [25] structure and deep depressions [23,25] and an increase in roughness (which is only possible using atomic force microscopy) of the films [4,19,21]. Also, while defining the influence of doping elements on the thermal stability of NiSi films, the roughness values and film morphology identified by the AFM method make it possible to estimate either the improvement or deterioration of its stability.…”