Defects were studied in epitaxial (001) ceria films that had been deposited and smoothed  in situ  on patterned (001) LaAlO3 substrates by means of ion beam assisted deposition. A hill-and-valley structure, with steps running parallel to the [100] LaAlO3 axis, was produced on the substrate surface by using photolithography and ion beam etching before deposition. An approximately 100nm-thick conformal epitaxial ceria layer was deposited onto the heated substrate by means of electron beam evaporation. The lattice-matching between the electron-beam film and the substrate was of the form:

(001)CeO2||(001)LaAlO3 and [110]CeO2||[100]LaAlO3

Evaporative deposition of additional film material onto the conformal layer was accompanied by bombardment with a 500eV Ar/O ion beam so as to promote  in situ  smoothing. Extreme lattice misfit for the orientation:

(001)CeO2||(001)LaAlO3 and [001]CeO2||[001]LaAlO3

caused the formation of dislocations in electron-beam ceria films in the vicinity of individual ledges in the substrate surface.

P.C.McIntyre, B.P.Chang, N.Sonnenberg, M.J.Cima: Journal of Electronic Materials, 1995, 24[6], 735-46