| Project/Area Number |
16360016
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thin film/Surface and interfacial physical properties
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| Research Institution | University of Tsukuba |
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Principal Investigator |
YAMABE Kikuo University of Tsukuba, Graduate School of Pure and Applied Sciences, Professor, 大学院・数理物質科学研究科, 教授 (10272171)
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| Co-Investigator(Kenkyū-buntansha) |
UEDONO Akira University of Tsukuba, Graduate School of Pure and Applied Sciences, Associate Professor, 大学院・数理物質科学研究科, 助教授 (20213374)
HASUNUMA Ryu University of Tsukuba, Graduate School of Pure and Applied Sciences, Assistant Professor, 大学院・数理物質科学研究科, 講師 (90372341)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥7,600,000 (Direct Cost: ¥7,600,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2004: ¥5,400,000 (Direct Cost: ¥5,400,000)
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| Keywords | High-k Dielectrics / Integrated Circuits / Gate Dielectrics / Conduction Mechanism / Charge Trapping / Reliability / Silicon Dioxide / Oxygen Deficiency |
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| Research Abstract |
In this study, we measured and evaluated dielectric characteristics of HfO_2-based gate oxide films as a tyical metal oxide film, of which application to ULSI is developed.
To suppress instability of electric characteristics at Si surface, thin interlayer silicon dioxide is inserted between the high-k film and Si substrate. It is pointed out that the interlayer film is attacked during adhesion of metal atoms and their dielectric characteristics are degraded. This result means that in manufacturing process of the metal oxide films, the dielectric characteristics of the interlayer thin films can be degraded.
It is cleared that conduction of such thin high-k metal oxide films is limited not by interface but by their bulk quality. Carrier separation method of gate leakage currents gives us understanding that both electrons and holes contribute to conduction. Both electron and hole currents are attributed to conduction of intermediate defect levels such as oxygen deficiencies and oxygen inter
… More
stitials. To stabilize the leakage currents, it is important that these defects are excluded or controlled. Time dependence of both electron and hole currents is explained by non-uniform distribution of both trapped electrons and trapped holes. That is, the electrons are trapped near the gate electrode in the high-k gate dielectric films and the holes are trapped near the substrate.
Study using mono-energetic positron beams gives us the evidence of oxygen deficiencies in high-k gate films. This study shows relationship between oxygen deficiencies and electric characteristics of high-k metal oxide thin film. Addition of nitrogen to high-k metal oxide films suppresses the gate leakage currents and their deviation. First principle calculation supports the effect of nitrogen addition.
To realize high-performance function of integrated circuits by various kinds of thin metal oxides, it is shown that establishment of both more precise manufacturing processes of metal oxides and their evaluation technologies is necessary and collaboration of experimental and calculation physics is very important. Less
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