Microhardness properties of Cu–W amorphous thin films

Abstract

Pure copper, pure tungsten and amorphous Cu₅₀W₅₀ and Cu₆₆W₃₄ alloy films were deposited by the direct current magnetron sputtering technique on cooled glass substrates. The film microhardness has been investigated as a function of alloy composition and substrate potential bias during deposition. The microhardness exhibited a maximum at Cu concentrations close to 50 at%, similar to the case of completely miscible binary alloys. The ion bombardment caused by the negative substrate polarization increased the film microhardness. The annealing of the amorphous Cu–W films up to 250 °C in vacuum increased the film microhardness by 10–20% apparently owing to the formation of the W(Cu) crystalline phase dispersed within a predominantly amorphous film matrix.