We investigated the characteristics of Ag films with and without an Al surface layer deposited by radio frequency magnetron sputtering in different gases. Using Kr gas, the films showed a lower electrical resistivity and larger crystallite size than those sputtered in Ar gas. An Al/Ag film with an Al thickness of 1 nm had a reflectance equivalent to that of a non-coated Ag film because the surface Al layer was fully transformed into a transparent Al oxide layer. To investigate the durability of the films, an environmental test was conducted at a temperature of 55 °C and a relative humidity of 90% for 16 h. It was found that the Al/Ag films suffered no degradation during this test.
