Microstructure of ruthenium dioxide films grown on {alpha}{endash}Al{sub 2}O{sub 3} (0001), {alpha}{endash}Al{sub 2}O{sub 3} (1{bar 1}02), and SrTiO{sub 3} (100) using reactive sputtering
- Departments of Chemistry and Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 (United States)
- Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 40439 (United States)
A quantitative study was made of the composition and microstructure of RuO{sub 2} films deposited on three different substrates using reactive sputtering. Most of the films had a composition within 2.5 wt.{percent} of the correct stoichiometry; the only exceptions were films grown on Al{sub 2}O{sub 3}(0001) at 150{degree}C, which had an oxygen-to-ruthenium ratio of 1:2.24. The excess oxygen was attributed to a thin oxygen-rich layer that encapsulated the grains. Hydrogen concentrations for the films deposited on Al{sub 2}O{sub 3}(0001) were 14, 6, 6, and {lt}0.5 at.{percent} for room, 150, 300, and 450{degree}C growth temperatures respectively. The films deposited at room temperature were amorphous on Al{sub 2}O{sub 3}(0001) and SrTiO{sub 3}(100), but weakly crystalline on Al{sub 2}O{sub 3}(1{bar 1}02). Highly oriented RuO{sub 2}(100) films were produced on Al{sub 2}O{sub 3}(0001) at deposition temperatures {ge}150{degree}C. The in-plane alignment was [010]{sub RuO{sub 2}}//{l_angle}{bar 2}110{r_angle}{sub Al{sub 2}O{sub 3}} and a threefold mosaic microstructure was observed. The grain boundaries in these films were discontinuous until the substrate temperature was raised to 450{degree}C, where coherent grain boundaries were formed. The films grown on Al{sub 2}O{sub 3}(1{bar 1}02) at 450{degree}C exhibited the epitaxial relationship: RuO{sub 2}(101)//Al{sub 2}O{sub 3}(1{bar 1}02). The in-plane alignment was RuO{sub 2}{l_angle}101{r_angle}//Al{sub 2}O{sub 3}{l_angle}{bar 1}101{r_angle}, and the lattice parameters were the same as found in bulk RuO{sub 2}. Transmission electron microscopy indicated a large degree of imperfection in the region between coalescing grains. The RuO{sub 2} films grown on SrTiO{sub 3}(100) at room temperature were amorphous. The film grown at 450{degree}C showed a preferential orientation with RuO{sub 2}(100)//SrTiO{sub 3}(100), but without in-plane orientation. {copyright} {ital 1997 Materials Research Society.}
- OSTI ID:
- 491633
- Journal Information:
- Journal of Materials Research, Vol. 12, Issue 4; Other Information: PBD: Apr 1997
- Country of Publication:
- United States
- Language:
- English
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