| Project/Area Number |
10555002
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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 | 展開研究 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
FUKATSU Susumu The University of Tokyo, Graduate School of Arts and Sciences, Associate Professor, 大学院・総合文化研究科, 助教授 (60199164)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAMOTO Kiyoshi The University of Tokyo, Graduate School of Arts and Sciences, Assistant Professor, 大学院・総合文化研究科, 助手 (40302822)
TANI Yukara Japan Fine Ceramics Center, Researcher, 研究員
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥7,600,000 (Direct Cost: ¥7,600,000)
Fiscal Year 1999: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1998: ¥6,200,000 (Direct Cost: ¥6,200,000)
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| Keywords | Hybrid epitaxy / Epitaxial Si / SiOィイD22ィエD2 heterostructures / SiGe virtual substrate / SiGe / SiOィイD22ィエD2 quantum structures / Ge content ceiling in SiGe-OI / Near-surface optical absorption band / 半導体ヘテロ構造 / ワイドギャップ・低誘電率 / 非晶質シリコン酸化物障壁 / エピSi / 電子・光の閉じ込め / SiGe混晶ベース量子構造 / 高密度励起子 |
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| Research Abstract |
A novel technique is developed to create truly "epitaxial" Si/SiOィイD22ィエD2-based heterostructures. The new technique is a variant of Si molecular beam epitaxy which features a low-energy oxygen ion implanter, referred to as hybrid epitaxy. Controlling the kinetics of internal oxidation and disruption of Si encompassed by a wide-gap SiOィイD22ィエD2 matrix in a separation-by-implanted oxygen (SIMOX) geometry allows a rich variety of Si/SiOィイD22ィエD2- and SiGe/SiOィイD22ィエD2-based quantum nanostructures. Fabrication of Si quantum wells, quantum wires using either a V-grooved substrate or cleave-edges of SIMOX, and a stacked array of quantum dots have been successful. What characterizes most such a wide spectrum of quantum structures is the fact that the Si or SiGe features maintain crystalline coherence transmitted from the substrate. As a result, Si and SiGe quantum dots are of highly-oriented nature, i.e., the feature hardly attainable otherwise.
In view of conceivable applications, an attempt
… More
was made to fabricate key components in the field of optoelectronics. For example, creating Bragg mirrors offering a normal incidence reflectance of 90% at designated stop-band wavelengths has enjoyed much success, which in turn has a high potential for use as a virtual substrate for regrowth. In the same context of virtual substrate, SiGe-OI structures recently have become of particular importance to the electronics as they not only comply with the demand for SOI but a high electron mobility transistor can be readily obtained simply by growing a tensilely-strained Si channel atop. Thoroughly studying the energetics and kinetics of the evolution of SiGe-OI, it has been found that a good SiGe-OI is permitted in a narrow window region in tens of the Ge contents and accordingly there is a x-value ceiling (x<0.3) for the starting SiィイD21-xィエD2GeィイD2xィエD2 layers which may or may not have been strain-relaxed. Selective oxidation of Si and concomitant desorption of GeO due to a thermal budget given to the samples during the annealing step of the SIMOX process is responsible for the erosion or total loss of SiGe for x values larger than 0.3. In contrast, by using SiGe alloys with x<0.18, a record value of 8-nm was obtained as the thickness of the top SiGe.
An interesting observation made for SiGe-OI is the development of a strong optical absorption band located around 1.2eV. The new band shows up only after oxidation and is originated from the near-surface region which was confirmed as quenching of the bulk photocurrent for a series of MSM Schottky-type photodetectors in a lateral configuration. Less
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