Artificially introduced [001] tilt boundaries in epitaxial thin films were prepared by deposition onto SrTiO3 bi-crystalline substrates. They were then examined by means of transmission electron microscopy and atomic force microscopy. It was found that the grain boundary deviated from the path that was defined by the underlying substrate boundary; with the so-called meandering Cu3Ba2YOx boundary only generally following the path that was defined by the boundary in the substrate. The atomic force microscopic studies suggested that the meandering behavior was related to the nucleation and growth mechanisms of the film. On this basis, it was found to be possible to vary the degree of meandering by changing the growth conditions. The implication of this meandering behavior was that potential variations in electrical behavior could occur from point to point along these boundaries. This effect was likely to be exacerbated by reduced junction line-widths.

D.J.Miller, T.A.Roberts, J.H.Kang, J.Talvacchio, D.B.Buchholz, R.P.H.Chang: Applied Physics Letters, 1995, 66[19], 2561-3