Effects of Nb Surface and Ti Interface Layers on Thermal Stability and Electrical Resistivity of Ag Thin Films

Abstract

Nb/Ag, Ag/Ti, and Nb/Ag/Ti films were prepared by rf magnetron sputtering to investigate the effects of the Nb surface and Ti interface layers on the thermal stability and electrical resistivity of 100-nm-thick Ag thin films. The Nb surface layer, regardless of the chemical state of metal or oxide, prevented the migration of Ag atoms during annealing, which contributed to the agglomeration suppression of Ag films. Ti interface layers not only improved the adhesion of Ag films to SiO2 substrates but also impelled the overcoated Ag atoms to arrange along the close-packed plane (111); thus, Ag/Ti films exhibited relatively good thermal stability and low resistivity. By combining the roles of the Nb surface and Ti interface layers, Nb (5 nm)/Ag (100 nm)/Ti (3 nm) films showed the highest thermal stability and the lowest resistivity. Different materials of surface and interface layers might be more effective for improving the thermal stability and electrical resistivity of Ag films.