The atomic motion of O in a c-axis oriented film was studied by using implanted 18O as a tracer. Conventional annealing (1h, 175 to 550C) was performed in a flowing O ambient. Secondary ion mass spectroscopic analysis showed that the implanted isotope began to migrate within the oxide film at temperatures of between 250 and 300C. The results of gas/solid O isotopic exchange showed that, at 315C, the O could enter the oxide film. This confirmed a high mobility of O within the film, even at this low temperature. The apparent volume diffusivity of the O at 315C was found to be about 1.5 x 10-13cm2/s. Short-circuit diffusion was suggested to play an important role in determining the high mobility of O in the c-axis oriented film.

Y.Li, J.A.Kilner, T.J.Tate, M.J.Lee, R.J.Chater, H.Fox, R.A.De Souza, P.G.Quincey: Physical Review B, 1995, 51[13], 8498-502