1996 Fiscal Year Final Research Report Summary
Dynamic Processes in Atomic Level on Silicon Surfaces
| Project/Area Number |
07455022
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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, 工学部, 教授 (00023292)
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| Co-Investigator(Kenkyū-buntansha) |
HORIO Yoshimi Nagoya University Department of Quantum Engineering Assistant Professor, 工学部, 助手 (00238792)
AKIMOTO Koichi Nagoya University Department of Quantum Engineering Associate Professor, 工学部, 助教授 (40262852)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Silicon surfaces / Adsorption / Epitaxial growth / Metal adsorption / Scanning tunneling microscopy / reflection high-energy electron diffraction / X-ray diffarction / Metal-silicon interface |
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| Research Abstract |
Thermal relaxation of isolated silicon islands and craters on the Si(111)7*7 and the Si (001)2*1 surfaces have been observed by temperature variable scanning tunneling microscopy (STM). Thermal decomposition rates of silicon islands and filling-up rates of craters were measured at various substrate temperatures of 300 to 600ﾟC.Effects of the probe tip on the rates were measured and the reduced rates were determined without the tip effects. Sizes of islands and craters depend on time t with a functional form of (t<@D20@>D2-T)<@D1a@>D1, and alpha*1 without tip effects and alpha*2/3 under the tip effects. For the Si (111) surface activation energies for island decomposition and crater filling-up were determined as 1.5(]SY.+-。[)0.1 eV and 1.3(]SY.+-。[)0.2 eV,respectively. Pre-exponential factors are 2*10<@D111(]SY.+-。[)1@>D1/s for islands and 3*10<@D19(]SY.+-。[)2@>D1/s for craters. We have found that characteristic 5*5 islands with long life time are formed during relaxation, but the 7*7 i
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slands have mostly short life time. Rotation of small islands was also observed during relaxation. For Si (001) islands an activation energy was determined as the value of 2.1(]SY.+-。[)0.5 eV.The pre-exponential factor is 10<@D118(]SY.+-。[)4@>D1/s. The rates of the relaxation of Si (001) islands are about 100 times larger than those of Si (111) islands. The characteristic islands on the Si (001) surface have rectangular shapes with aspect ratios near 3 : 1.
Gold and silver growth on Si (111)ROO<3>*ROO<3> -Au and -Ag surfaces were investigated by reflection high-energy electron diffraction (RHEED), STM and X-ray diffraction. At temperatures lower than 100ﾟC,gold is grown epitaxially on the ROO<3>*ROO<3> -Au and ROO<3>*ROO<3> -Ag surfaces with layr-by-layr mode. In this case, gold silicide layr segregates on the grown layr. At temperatures higher than 200ﾟC,growth of the gold becomes island mode. We specurate that the change of the growth mode is due to eutectic temperature of the two dimensional gold silicide layr segregated on the grown surfaces. For silver growth on the both surfaces, segregation of silicide layrs does not take plance. Silver layr is grown epitaxially on the ROO<3>*ROO<3> -Au with nearly layr-by layr mode at the low temperatures. On the ROO<3>*ROO<3> -Ag surface, however, island growth mode takes place. In this case, growth structure of the silver layrs depends strongly upon temperature. We have found that interface structures between silicon substrate and silver layrs also depend upon the temperature, and are related to the structures of the growth layrs. Less
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