Effect of sputtering power on the microstructure and properties of silver films prepared by magnetron sputtering

Tailoring the microstructure of deposited films to enable the desired properties is crucial for their specific applications. This paper thoroughly investigates the influence of sputtering power on the microstructure evolution and properties of silver (Ag) films deposited using magnetron sputtering technology. Variations in sputtering powers yielded distinct microstructures, including surface morphology, grain size, and texture. Specifically, as the sputtering power increased from 100 to 300 W, the microstructure characteristics of Ag films evolved from randomly oriented nanocrystalline grains to (111)-preferred-oriented columnar grains with high-density twins, and eventually to equiaxed micron-sized grains displaying strong (111) out-of-plane texture. Analysis in junction with substrate temperature measurements and the structure zone model (SZM) revealed that increased sputtering power influenced grain growth mode during film thickening by raising the substrate temperature, and ultimately the microstructure. Property testing results indicated that nanotwinned Ag films deposited at 200 W exhibited an exceptional combination of hardness and electrical conductivity, owing to the strengthening effect of nanotwins. These films achieved a hardness of 2.13 GPa and an electrical conductivity of 58.65 MS/m. These findings advance the understanding of how sputtering power influences microstructure, presenting a new avenue for optimizing sputtered Ag film for diverse engineering applications.