Study On Structure And Properties Of Silver Thin Films Deposited By Magnetron Sputtering Under The Atmosphere Containing N₂

Magnetron sputtering method has the characteristics of high deposition rate and excellent films quality,and silver thin films are often prepared by magnetron sputtering in Ar.The microstructure of the silver thin films changes when N2 was added as sputtering gas.Moreover,functional layers with the multilayer structure such as silver/nitride are usually used in electronic devices.While the silver/nitride thin films with the multilayer structure are continuously prepared by magnetron sputtering method,the sputtering gas need to change,and the preparation process of silver/nitride thin films is complex.Therefore,the preparation of silver thin films in Ar/N2 mixed atmosphere has a scientific significance in analyzing the structure and structural evolution mechanism of silver thin films.It also has engineering guiding significance in simplifying the preparation process of multilayer silver/nitride functional coatings.In this paper,silver thin films were prepared by magnetron sputtering.The effects of N2 content on the microstructure and properties of silver thin films in Ar/N2 mixed atmosphere were investigated.The microstructure of silver thin films was analyzed by XRD,SEM and XPS,and the influence of N2 content on its corrosion resistance,optical property,electrical property and bonding strength property between films and substrate were discussed.The research results are as follows:The phase of silver nitride in silver thin films wasn't observed when N2 was introduced as a working gas,but the microstructures such as grain orientation,grain size and surface morphology changed significantly.The silver thin films prepared in Ar exhibit(111)preferred orientation.With the increase of N 2 content in Ar/N2 mixed atmosphere,the preferred growth orientation of grains changes from(111)to(100).The average grain size of the silver thin films decreases firstly and then stabilizes with the increasing of N2 content in Ar/N2 mixed atmosphere.Moreover,the surface of silver thin films prepared in low N2 content are smooth and flat,and the structure of films is dense.While the N2 content arrived to above 50 vol.%,a lot of voids existed on the surface of films,and the relative density of the films decreases.The results show that the energy change of sputtered Ag particles in Ar/N2 atmosphere is the main reason for the change of the microstructure of silver thin films.The surface of silver thin films prepared in low N2 content is smooth,flat,and relatively dense,and,silver thin films prepared in low N2 content have higher corrosion resistance,higher specular reflectance,lower resistivity and higher bonding strength.When the N2 content is less than 33.3 vol.%,the average grain size of the silver thin films decreases with the increasing N2 content in Ar/N2 mixed atmosphere.Thus,the resistivity of films increased due to grain boundary scattering.With the further increasing N2 content,the number of pores in silver thin films increased,and the relatively density of the films decreased.So,the resistivity of the silver thin films increased due to the defects scattering.The bonding strength between films and substrate decreases with the increasing N2 content in Ar/N2 mixed atmosphere,and the loose and porous structure is the main factor leading to a weak bonding strength.In summary,No silver nitride formed in silver thin films prepared by magnetron sputtering in Ar/N2 mixed atmosphere.The introduction of an appropriate amount of N2 can not only conveniently regulate the grain orientation of silver thin films,but also obtain silver thin films with high relatively density and good properties.