A mechanism was proposed, for so-called room-temperature electric-field induced O diffusion, which was based upon the interface reaction of Al/yttria-stabilized zirconia and on measurements of film-leakage properties. Application of a positive electric field (1MV/cm) to a 25nm-thick and 200µm-diameter Al top electrode on a YSZ/Si thin film, changed the color of the Al top electrode from silver to black in 400s. This was due to Al oxidation; as confirmed by secondary ion mass spectrometry and X-ray photo-electron spectroscopy. Electrically-induced diffusion of O ions from the yttria-stabilized zirconia, and into the Al electrode, caused this oxidation. This phenomenon was not observed when a negative field was applied. It was also not exhibited by an Al/SiO2/Si thin film when a positive field (50MV/cm) was applied. This method could detect redox reactions between the Al top electrode and the material; thus indicating O diffusion at low temperatures.

Room-Temperature Electrical-Field Induced Oxygen Diffusion of Aluminum/Yttria-Stabilized Zirconia Thin Film Grown on Si Substrate. N.Wakiya, N.Tajiri, T.Kiguchi, N.Mizutani, J.S.Cross, K.Shinozaki: Japanese Journal of Applied Physics, 2006, 45[11], 8827-31