Interdiffusion between layers in multi-layer ferroelectric thin films was studied by using secondary ion mass spectrometry to analyze the depth profiles. Among the films which were deposited onto Cu3Ba2YO7/CeO2/Si substrates, it was noted that interdiffusion was most marked in the case of (Sr0.5Ba0.5)Nb2O6 films. The higher substrate temperatures which were used to grow these films were believed to be the main cause of this. Interdiffusion was less marked in the case of films of Pb0.97La0.03(Zr1-xTix)0.9925O3, where x was equal to 0.54 or 0.34. The larger proportion of cationic vacancies which existed in these films was suggested to be another possible cause of enhanced interdiffusion. The latter was most insignificant in the case of BaTiO3 films. It was concluded that the use of Cu3Ba2YO7/SrTiO3 as a substrate greatly reduced interdiffusion between layers. This was attributed to the superior crystallinity of the Cu3Ba2YO7 layers that were deposited onto SrTiO3 substrates.

J.P.Wang, Y.C.Ling, I.N.Lin, W.J.Lin, T.Y.Tseng: Journal of Applied Physics, 1996, 79[10], 7621-6