| Project/Area Number |
05650682
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Structural/Functional materials
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| Research Institution | University of Osaka Prefecture |
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Principal Investigator |
MORII Kenji University of Osaka Prefecture, College of Eng.Associate, Professor, 工学部, 助教授 (10101198)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUI Tosiyuki University of Osaka Prefecture, College of Eng.Research Associate, 工学部, 助手 (20219372)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1993: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | dielectric thin films / amorphous thin films / relative dielectric constant / dissipation loss / temperature dependence of epsilon / frequency dependence of epsilon / dielectric relaxation / titanate dielectrics / チタン酸ストロンチュウム / 周波数依存性 / SiTiO_3-BaTiO_3 |
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| Research Abstract |
Dielectric thin films which have a high permittivity, high elctrical resistivity and flat frequency response have attracted much attention as indispensable materials for various electronic as well as optical devices. The dielectric properties of bulk crystalline materials can now be controlled so as to fit most of their applications by adjusting material factors such as the crystal structure, grain size and boundary phases. In contrast to this, many dielectric thin films show rather poor properties due mainly to versatile restrictions coming from the conditions for thin film preparation and post deposition heat-treatments. Microstructural control in thin film materials seems to be difficult to perform when only the crystaline films are taken into account.
In this study, we focused the amorphous thin films to avoid such difficulties in the crystals. Since the amorphous structure is accompanied by a rather high degree of freedom in local atomic arrangements, the short range order in the amorphous films could be changed by, for example, thermal annealing and impurity doping. This may provide a possibility for controlling the dielectric properties in the amorphous thin films. The aim of this study is to fabricate the amorphous dielectric thin films and to examine the correlation between the short range structure and dielectric properties in these films. The main results are summarized as follows :
The amorphous thin films of SrTiO_3 and BaTiO_3 exhibited a marked temperature and frequency dispersion of the permittivity below the crystallization temperature of about 900 K.Its maximum value is comparable to that for the bulk crystals. The charged oxygen vacancies are supposed to play an importnat role in this behavior. It is concluded that the amount of oxygen deficiency can be regarded as being one of effective factors to control the dielectric properties of the amorphous films.
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