The effect of the Cr and Mo on the surface accumulation of copper in the electrodeposited Ni–Fe/Cu alloy films

In the present study, the surface chemical and depth profile composition of the electrodeposited Ni–Fe base alloy layers on the Cu substrates were investigated with compositions of the Ni80–Fe20 (binary) and Ni77–Fe20.7–Cr1.7–Mo0.6 (quaternary) deposits. Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) results showed the surface accumulation of copper on the surface layers of binary alloy films in the form of Cu2O. In the quaternary films, addition of Cr and Mo reduced the amount of the Cu accumulation at the surface, while Cu accumulation was enhanced under air-exposed condition for both alloy films. Depth profiles using the secondary ion mass spectroscopy (SIMS) revealed that in the binary layers, the amount of oxide phases of the Ni–Fe was greater than that quaternary deposit. It is concluded that addition of the Cr and Mo impurities reduced the amount of the copper at the surface layers and oxygen inside the quaternary films.