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Single crystals of a new quaternary oxide, barium hexadecayttrium tetrasilicon tritriacontaoxide, BaY16Si4O33, were obtained from a melt-solidified sample prepared by heating a mixture of BaCO3, Y2O3, and SiO2 at 2073 K. X-ray crystal structure analysis revealed that Ba(SiO4)4 orthosilicate clusters in which a Ba atom is surrounded by four SiO4 tetrahedra were isolated in a framework composed of Y and O in the structure of BaY16Si4O33. The dielectric constant measured for polycrystalline ceramics of BaY16Si4O33 sintered at 1953 K was 13 (298 K, 1 MHz), and the thermal expansion coefficient was 8.70 × 10-6 K-1 (298-873 K), which are close to the values previously reported for Y2O3. [ABSTRACT FROM AUTHOR]

The thermal atomic layer deposition (ThALD) of yttrium oxide (Y2O3) was developed using the newly designed, liquid precursor, Y(EtCp)2(iPr2-amd), as the yttrium source in combination with different oxygen sources, such as ozone, water and even molecular oxygen. Saturation was observed for the growth of the Y2O3 films within an ALD window of 300 to 450 °C and a growth per cycle (GPC) up to 1.1 Å. The resulting Y2O3 films possess a smooth and crystalline structure, while avoiding any carbon and nitrogen contamination, as observed by X-ray photoelectron spectroscopy (XPS). The films showed strong resistance to fluorine-containing plasma, outperforming other resistant materials, such as silicon oxide, silicon nitride and alumina. Interestingly, the hydrophilic character exhibited by the film could be switched to hydrophobic after exposure to air, with water contact angles exceeding 90°. After annealing under N2 flow at 600 °C for 4 min, the hydrophobicity was lost, but proved recoverable after prolonged air exposure or intentional hydrocarbon exposure. The origin of these changes in hydrophobicity was examined. [ABSTRACT FROM AUTHOR]