| Project/Area Number |
13852009
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| Research Category |
Grant-in-Aid for Scientific Research (S)
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| Allocation Type | Single-year Grants |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TORIUMI Akira The University of Tokyo, School of Engineering, Professor, 大学院・工学系研究科, 教授 (50323530)
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| Co-Investigator(Kenkyū-buntansha) |
KYUNO Kentaro The University of Tokyo, School of Engineering, Lecturer, 大学院・工学系研究科, 講師 (40251467)
KITA Kita The University of Tokyo, School of Engineering, Research Associate, 大学院・工学系研究科, 助手 (00343145)
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| Project Period (FY) |
2001 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥119,210,000 (Direct Cost: ¥91,700,000、Indirect Cost: ¥27,510,000)
Fiscal Year 2005: ¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000)
Fiscal Year 2004: ¥8,840,000 (Direct Cost: ¥6,800,000、Indirect Cost: ¥2,040,000)
Fiscal Year 2003: ¥20,930,000 (Direct Cost: ¥16,100,000、Indirect Cost: ¥4,830,000)
Fiscal Year 2002: ¥30,160,000 (Direct Cost: ¥23,200,000、Indirect Cost: ¥6,960,000)
Fiscal Year 2001: ¥53,040,000 (Direct Cost: ¥40,800,000、Indirect Cost: ¥12,240,000)
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| Keywords | high-k dielectrics / hafnium oxide / yttrium oxide / lanthanum oxide / silicon / germanium / polarizability / amorphous / HfO_2 / La_2O_3 / Y_2O_3 / High-k膜 / Y-doped HfO_2 / 遠赤外特性 / LaYO_3薄膜 / Y_2O_3 on Ge / 界面層 / HfO2 / Y2O3 / シリケート / 光学フォノン / 高誘電率膜 / 基板面方位 / 界面制御 / 酸化レート / 原子状酸素 / 斜入射X線反射率測定 / 分光エリプソメトリー / Open Circuit Potential法 / スパックリング / オープンサーキットポテンシャル / オフアクシススパッタリング / ゲート絶縁膜 / MISキャパシタ |
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| Research Abstract |
This research target was to scientifically judge the possibility of usability of ultra-thin high-k dielectric films for next generation CMOS ULSI. Main results obtained are described below.
1.Understanding of origin of high dielectric constants of high-k materials proposed and constructing a guiding principle of high-k materials design.
(1)Phonon modes of high-k materials have been clearly provided using far-infrared absorption analysis.
(2)Y or Si doping into HfO2 can enhance the dielectric constant (〜30) through the phase transformation.
(3)La doping can enhance crystallization temperature as well as dielectric constant.
(4)The dielectric constants were quantitatively analyzed through both molar volume change and molar polarizability and a guiding principle for designing high-k dielectrics was proposed.
2.Understanding and control of high-k/Si interface layer
(1)The interface layer growth at HfO2/Si was modeled as parameters of substrate orientation, oxidation time, and temperature. This fact has clarified that high-k/Si interface layer growth mechanism is significantly different from Si surface oxidation.
(2)By taking account of atomic oxygen as oxidation species the interface layer growth model was quantitatively constructed and a guiding principle for the interface layer control was proposed.
Based upon those results, we challenged to demonstrate sub-nm EOT high-k oxides. Though still some optimization was needed for the interface characteristics improvement, we have achieved high-k gate stack with EOT=0.8 nm and 5 orders smaller leakage current compared to SiO2 case. Thus, the numerical target of this research has been fully achieved.
Furthermore, high-k dielectrics on Ge were also partly studied and new features of this system, particularly in the interface layer, have been observed. This result provides us a new research target for the next generation ULSI devices.
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