Preprints of Annual Meeting of The Ceramic Society of Japan<br> Preprints of Fall Meeting of The Ceramic Society of Japan

The hydrothermal reaction of slaked lime and silica sand containing feldspar and clay minerals as impurities have investigated. It was found that the flexural strength of the solidified bodies increased with increasing treatment temperature and time and was proportional to the amount of reaction products but independent of their type. Hydrogarnet and C-S-H were formed in the initial stages of reaction as precursors of 1.1 nm tobermorite and the amount of these phases tended to decrease and 1.1 nm tobermorite formed as the reaction progressed further. And the reaction was controlled by the diffusion of Si fraction from kinetic study.

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Thermal stability of amorphous phase La₂O₃-Ta₂O₅-ZrO₂ gate dielectrics has been investigated. The 15mol% La₂O₃-15mol%Ta₂O₅ doped ZrO₂ films after rapid thermal annealing (RTA) at 700degree C has maintained the amorphous phase without any phase separation. Those above 800degree C has crystallized, and shown the poly-crystalline nano-structure. These results can be comparable with the conventional Zr-silicate.

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Oxide artificial superlattices have the potential to drastically improve properties of conventional materials. We have demonstrated BaTiO3/SrTiO3 artificial superlattices made by an MBE process showed giant dielectric permittivity. However, the MBE process is not suitable for industrial production process because of it low deposition rate. Therefore in this study, we try to fabricate BaTiO3/SrTiO3 multi-layered films on MgO (001) substrates by RF sputtering method. BaTiO3 and SrTiO3 were alternately deposited using two ceramic targets. A solid solution film with a chemical composition of (Ba0.5Sr0.5)TiO3 was also prepared. X-ray pole figures indicated that the films had an epitaxial relation with the substrate. Planer electrodes were formed on the films using a lithography technique. The complex admittance of the thin film were measured with an impedance analyzer at 1MHz to 3GHz. Dielectric permittivity of the films was determined from admittance data using an electromagnetic field analysis. The film of [(BaTiO3)10/(SrTiO3)10]50 showed a high dielectric constant of 850 in comparison with the solid solution film.

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High performance integrated passives, such as capacitors and inductors, are in increasingly higher demand in modern wireless systems. Much effort has been focused on developing single chip module using air-core inductors and capacitors with low-dielectric constant films. However, at present this technology has a number of limitations for designing passives of large inductance and capacitance values on restricted semiconductor substrate area. Technologies of high performance magnetic and dielectric films and integration processes are essential for the purpose of reducing manufacturing cost, size, weight, and improve performance and battery life of modern communications products. In this paper we present an overview of thin film passives and their integration processes with special focus on the thin film inductors with high-frequency magnetic thin films. In order to realize an excellent permeability-frequency response, larger values of saturation magnetization and anisotropy field are required while keeping the film thickness less than skin depth. Microstructure control is the effective technique for adjusting the properties of magnetic thin films. The terminated columnar structure of Fe-C layer with CoZrNb amorphous layer, discontinuous structure of multilayer films with layers less than 2 nm thickness, and inclined grain growth of CoFe-Al2O3 composite films are introduced as examples.

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