X-ray Characterization of Films Formed by Pulsed Laser Deposition on Cold Substrates from YBaCuO Targets

J.B. Pełkaa, W. Paszkowicza, P. Gierłowskia, S.J. Lewandowskia, M. Zielińskia, S. Barbanerab and M. Knappc aInstitute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland bInstitute of Solid State Electronics CNR via Cineto Romano 42, 00-156 Rome, Italy cDepartment of Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt, Germany

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Grazing-incidence X-ray diffraction supplemented with atomic force microscopy and secondary ion mass spectroscopy were applied to the characterization of films deposited by laser ablation on cold substrates from YBaCuO targets and subsequently irradiated with additional laser pulses of lower energy density. Evolution of X-ray diffraction pattern was observed as a function of irradiation dose. For the as-deposited films the pattern was typical of the amorphized solids. For the films irradiated with doses higher than the threshold, the pattern was enriched with the diffraction peaks, whose general features, like peak positions, widths and relative intensities were almost independent of the dose. The size of the crystallites was deduced from the peak widths to be not smaller than 12-16 nm. Comparison of the pattern with patterns of known phases indicates that, apart of the amorphous component, a structure with an admixture of some new metastable or high temperature phase(s) is formed during the process of pulsed laser annealing. The atomic force microscopy observations revealed that the surface roughness shows a pronounced minimum at low irradiation doses. The secondary ion mass spectroscopy investigation confirms that the strongest chemical changes (increase in concentration of yttrium and copper) due to irradiation with higher doses are observed in the near-surface film material.

DOI: 10.12693/APhysPolA.101.787 PACS numbers: 52.38.Mf, 81.15.-z, 68.55.-a