| Project/Area Number |
10044146
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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 |
表面界面物性
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| Research Institution | Nagoya University |
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Principal Investigator |
ICHIMIYA Ayahiko Nagoya University, Department of Quantum Engineering, Professor, 工学研究科, 教授 (00023292)
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| Co-Investigator(Kenkyū-buntansha) |
MINODA Kouki Tokyo Institute of Technology, Department of Science, Assistant Professor, 理学部, 助手 (20240757)
YAGI Katsumichi Tokyo Institute of Technology, Department of Science, Professor Emeritus, 理学部, 名誉教授 (90016072)
IWASAKI Hiroshi Osaka University, The Institute of Scientific and Industrial Research, Professor, 産業科学研究所, 教授 (00029901)
NAKAHARA Hitoshi Nagoya University, Department of Quantum Engineering, Assistant Professor, 工学研究科, 助手 (20293649)
UWAHA Makio Nagoya University, Department of Science, Associate Professor, 理学研究科, 助教授 (30183213)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥8,600,000 (Direct Cost: ¥8,600,000)
Fiscal Year 2000: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1998: ¥3,400,000 (Direct Cost: ¥3,400,000)
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| Keywords | Semiconductor surfaces / Adsorption, Desorption / Epitaxial growth / Steps dynamics / Scanning tunneling microscopy |
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| Research Abstract |
Step dynamics on semiconductor surfaces during epitaxial growth, adsorption, desorption, step bunching and thermal relaxation of nano structures have been investigated experimentally and theoretically. Surfactant effects on step behaviors result changing step energy and adsorption barrier height during epitaxial growth of silicon, GaAs and GaN.For high index surfaces, we have observed that formation processes of facets are due to adsorbates.
Thermal relaxation of isolated three dimensional (3D) mounds of silicon on the Si (111) 7×7 and the Si (001) 2×1 surfaces have been observed by temperature variable scanning tunneling microscopy (STM). The 3D mounds formed by an STM tip are like pyramids with certain facets. Two types of pyramids are produced on the Si (111). The pyramids with a production probability of 75% are normal stacking at the interface between the mound and the substrate, and are called type U.For mounds with a production probability of 25% which are in the twin relation of
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the U mounds, there is a stacking fault at the interface, and they are called type F.
Just after the production, the pyramid begins to decompose. For the Si (111) during the decomposition of the type U mounds, the facets of the pyramid transform into multi-bilayer steps. Finally the mound becomes a bilayer (2D) island with a truncated triangle shape. The surface structure of the 2D island is the 5×5 DAS one. The longer edges of the 2D island are along the unfaulted halves of the DAS structure of the substrate, while these edges are the shorter one of the pyramid. The decay process of the type F islands is layer-by-layer without step bunching. Decay rates of the type F mounds are about 3 times larger than those of the type U mounds. Since the production probability of type U mounds is also 3 times larger than that of the type F mounds, it seems that the difference of the decay rates between the type U and the type F is related to the difference of the production probability of the both mounds. Since the type F mounds have larger decay rate than the type U, the F mounds have higher energy state than the U mounds because of higher interface energy of the F mounds due to the stacking fault and the twin relation between the mound and the substrate. It is concluded that the difference of formation energies of the both U and F mounds are the same as the difference of activation energies of decays of the both types of the mounds : The energy state of the type F mounds is about 0.06eV higher than that of the type U mounds. We have measured height evolution of the pyramids during decay, and found that the height decay is due to the power law, t1/4., where t is the decay time. Such the simple law is predicted theoretically for infinite cone decay. It should be noted that such the simple law is in very good agreement with the experimental results of silicon pyramid decay. Less
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