Optical reflectivity improvement by upgrading metallic glass film quality

The effects of atomic-defect and free-volume amounts of metallic glassy film on the optical reflectivity and mechanical properties of the sputtered metallic glass thin films are explored. With a lower Ar working pressure and the proper post-annealing at temperatures slightly lower than the glass-transition temperature T_g, film free volumes and defects would reduce, resulting in better atomic bonding and higher film hardness/modulus, which in turn leads to lower electric resistivity and higher optical reflectivity. Annealing above T_g would induce crystalline structure which would lead to competition with the optical transition of the Drude free electrons and hinder the optical reflectivity in the visible range.