The rate of O diffusion into de-oxygenated films during O plasma oxidation at temperatures below 160C was studied. The films were de-oxygenated by annealing in N2 or Ar. The de-oxygenated film was tetragonal, and plasma oxidation changed the structure from tetragonal to orthorhombic. The final composition was estimated to be Cu3Ba2YO6.4. The diffusivity was deduced, from the time dependence of the weight gain, to be of the order of 10-12cm2/s.

A.Yoshida, H.Tamura, S.Morohashi, S.Hasuo: Applied Physics Letters, 1988, 53[9], 811-3