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Surface analysis of films and film systems produced by pulsed laser deposition



Fresenius Journal of Analytical Chemistry 353 (1995), pp.729-733
ISSN: 0937-0633
Journal Article
Fraunhofer ILT ()
boron-oxynitride species; ceramic coating; crystal structure; film systems; films; kinetic energy; plasma plume; PLD; pulsed laser deposition; stoichiometry; surface layer

Ceramic films and film systems (ZrO2 films, ZrO2/Ti multilayers, and BN films) are deposited by pulsed laser deposition (PLD) and analyzed using X-ray photoelectron (XPS), Auger electron (AES), and micro-Raman spectroscopies. The electron spectroscopies are used to determine the film stoichiometry, the nature of the bonding, and to specify contaminant species. The micro- Raman spectroscopy gives information on crystal structure, grain size, and mechanical stress within the films. In ZrO2 films a stoichiometry is achieved within typically 5%, with only weak dependencies on processing variables. The only contaminants are a small amount of water from the ambient gas and a carbonaceous surface layer. Multilayers consisting of alternating Zr02 and Ti layers exhibit a TiC contamination within the Ti layers. Depending on the processing variables, BN films may be nearly stoichiometric or may have significant, even dominant contamination's throughout the film from elemental B, B203, and/or a bo ron-oxynitride species. The first component is due to the non-stoichiometric material removal from the target (N-depletion) at low laser fluences, as confirmed by XPS measurements on irradiated targets. The second and third arise from H20 in the ambient, and exhibit a complex dependence on processing variables. Micro-Raman spectra show only amorphous or hexagonalphase BN. Depending on the position on the substrate relative to the laser-induced vapour/plasma plume, there may be a particle deposition or mechanical stress within the films, as evidenced from large shifts (up to 15 cm [-1]) of the Raman spectral peaks.