Investigation of oxidation resistance of Ni–Ti film used as oxygen diffusion barrier layer

Ni–Ti films prepared at 10 W and 70 W by rf magnetron sputtering are investigated as the oxygen diffusion barrier layer, it is found that crystallinity of Ni–Ti film does not greatly depend on the deposition power. X-ray photoelectron spectroscopy indicates that Ni is still in the form of metallic state from the binding energies of both Ni 2p3/2 and Ni 2p1/2 spectra for the sample with 10 W prepared Ni–Ti, however, Ni is oxidized for 70 W prepared Ni–Ti film. Moreover, the (La0.5Sr0.5)CoO3/Pb(Zr0.40Ti0.60)O3/(La0.5Sr0.5)CoO3 capacitor grown on high power prepared Ni–Ti film is leaky, however, the capacitor on low power prepared Ni–Ti film possesses very promising physical properties (i.e. remnant polarization of ∼27 μC/cm2 at 5 V and maximum dielectric constant of 940). Leakage current density of the capacitor grown on low power prepared Ni–Ti film is further investigated, it meets ohmic behavior (<1.0 V) and agrees well with the space-charge-limited current theory (>1.0 V).