| Project/Area Number |
10305026
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
MIYAZAKI Seiichi Facul.Eng., HIROSHIMA UNIVERSITY, Associate Professor, 工学部, 助教授 (70190759)
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| Co-Investigator(Kenkyū-buntansha) |
MURAKAMI Hideki Facul.Eng., HIROSHIMA UNIVERSITY, Research Associate, 工学部, 助手 (70314739)
KOHNO Atsushi Fukuoka University, Facul.Science, Lecturer, 理学部, 講師 (30284160)
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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 |
¥36,600,000 (Direct Cost: ¥36,600,000)
Fiscal Year 2000: ¥8,600,000 (Direct Cost: ¥8,600,000)
Fiscal Year 1999: ¥11,900,000 (Direct Cost: ¥11,900,000)
Fiscal Year 1998: ¥16,100,000 (Direct Cost: ¥16,100,000)
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| Keywords | Silicon / Quantum Effect / Quantum Dots / Low Pressure CVD / Location Control / Scanning Probe Microscope / Tunnel Current / 量子構造 / 自己組織化形成 / 原子間力顕微鏡 / 選択成長 / 表面化学結合 |
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| Research Abstract |
Self-assembling formation of silicon quantum dots (SiQDs) on ultrathin SiO_2 by low pressure CVD using silane (SiH_4) has been studied, and the formation mechanism for positioning SiQDs has been proposed and a practical process to control the arrangement of the SiQDs has been developed. In addition, for multiply-stacked SiQDs covered with very thin SiO_2, specific non-linear conductance and its temporal variation have been measured at room temperature. The major results and achievements of this research are as follows :
(1) Since Si-OH bonds on the SiO_2 surface act as reactive sites in SiH_4-LPCVD, the position control of the Si-OH bonds enables us to control the arrangement of the SiQDs on SiO_2.
(2) Area-selective nucleation for the Si dot arrangement is degraded seriously by surface contamination due to physisorption of hydrocarbons and/or water molecules, which is inevitable in exposure to clean room air.
(3) Surface modification techniques using a scanning probe microscope such as A
… More
FM or STM have been applied to form the Si-OH bonds out the SiO_2 surface intentionally at a certain position or area. Based on these techniques, a contamination-free process for the selective nucleation has been developed to realize highly-selective growth and precise positioning of the SiQDs.
(4) The double barrier structures of a SiQDs array sandwiched with ultrathin SiO_2 layers have been characterized by simultaneously-measured AFM topographic and current images, The results show that the resonant tunneling through each of the SiQDs depends on not only the dot size but also the difference in electron charging among the neighboring dots.
(5) The amount of electron charging into the SiQDs can be derived from the change in the local surface potential measured by operating an AFM tip with a Kelvin probe mode.
(6) The electron transport through multiply-stacked SiQDs covered with SiO_2, which were prepared by repeating the dot formation and the surface oxidation, has been studied and distinct random telegraph noise (RTN) in tunneling current, through coupled SiQDs has been measured even at room temperature. The bias voltage dependence of the frequency and the current variation in the RTN suggests that the observed RTN phenomenon can be interpreted in terms of electron charging and discharging in the dots being the neighbor of the tunneling path for coupled quantum dots. Less
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