Use of a synchrotron X-ray microbeam to map composition and structure of multimetallic metal oxide films deposited by combinatorial chemical vapor deposition

Using anhydrous metal nitrates as single source precursors, combinatorial chemical vapor deposition was used to create compositional gradients in the bimetallic ZrO₂/HfO₂ system and the trimetallic ZrO₂/HfO₂/SnO₂ system. Composition and structural information were probed simultaneously by measuring the fluorescence and diffraction resulting from exposure of the film to a 30 μm diameter X-ray beam at the Advanced Photon Source. The higher resolution made possible by the small beam size provided an accurate map of composition and structure. In the homologous zirconia-hafnia series a decrease in lattice constants and a change in film texture was observed as a function of increased Hf concentration. As reported elsewhere, at intermediate compositions, gradients involving ZrO₂ and SnO₂ or HfO₂ and SnO₂ give rise to a crystalline phase(α-PbO₂ structure type) that differs from that found for either of the end members. The simultaneous measurement of fluorescence and diffraction coupled with the small spot X-ray source provides a more accurate correlation between composition and structure.