Effects of dielectric film surface on oxygen diffusion

Abstract

The oxygen diffusivity in BaTiO 3 thin films heteroepitaxially grown on SrTiO 3 substrates was investigated using a gas/solid exchange technique with 18 O-isotope-enriched gas. Deformation of the BaTiO 3 lattice and inhibition of the oxygen diffusivity occurred simultaneously when the YSZ layer, which is assumed to be catalytic for the 18 O/ 16 O exchange reaction, was deposited on BaTiO 3 . The mechanism for the reduction in oxygen diffusivity due to the YSZ cover layer is discussed in terms of residual stress in the strained BaTiO 3 layer.

Interface Properties of Dielectric Oxides

“…During deposition of an oxide onto an oxide substrate, oxygen may diffuse from the substrate to oxidize the growing film. This has been reported, for example, during deposition of SrTiO 3 by PLD at 750°C onto different substrates . While such effects may contribute to the different behavior, they are not expected to be dominant due to the lower deposition temperature of ITO (400°C) and the abundance of oxygen in the sputter deposition process.…”

“…This is also strongly indicated by the observation that the barrier heights can be changed dramatically by postdeposition treatments, which will be presented in Section III ( C ). To which extend oxygen exchange between substrate and film during formation of heterostructures between two metal oxides, which changes defect concentrations in the substrate and the film, can also be an origin of Fermi level pinning is not yet elucidated.…”