Novel Si–Ge–C superlattices and their applications

Augusto, Carlos; Forester, L.

doi:10.1016/j.sse.2015.01.019

Cited by 7 publications

(5 citation statements)

References 25 publications

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“…Using a heteroepitaxial SL structure, a band gap and band offset can be engineered and novel material properties can be designed. 1,2) Additionally, by fabricating a nanodot structure, it is possible to change the density of states in the conduction band and valence band. 3,4) Therefore, threedimensionally (3D) stacked SiGe and Ge nanodots of SL are of interest because of their potential for designing new optoelectrical material properties.…”

Section: Introductionmentioning

confidence: 99%

Vertical alignment control of self-ordered multilayered Ge nanodots on SiGe

Wen

Schubert

Tillack

et al. 2023

Jpn. J. Appl. Phys.

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Self-ordered multilayered Ge nanodots with SiGe spacers on Si0.4Ge0.6 virtual substrate were fabricated by using reduced-pressure chemical vapor deposition, and the mechanism of vertical ordering was investigated. Process conditions of Ge and SiGe layer deposition are H2-GeH4 at 550 °C and H2-SiH4-GeH4 at 500 °C - 550 °C, respectively. By depositing the SiGe at 550 °C or raising Ge content, the SiGe surface becomes smooth, resulting in vertically-aligned Ge nanodots to reduce strain energy. Ge nanodots prefer to grow on the nanodot where the SiGe is relatively tensile strained due to the buried Ge nanodot underneath. By depositing at 500 °C and lowering Ge content, checkerboard-like surface forms, and the following Ge nanodots grow at staggered positions to reduce surface energy. The Ge nanodots are laterally aligned along elastically soft <100> direction without pre-structuring resulting from the strain distribution.

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Section: Introductionmentioning

confidence: 99%

Vertical alignment control of self-ordered multilayered Ge nanodots on SiGe

Wen

Schubert

Tillack

et al. 2023

Jpn. J. Appl. Phys.

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“…Recent group IV semiconductor fabrication technologies enable the realization of new artificial materials such as superlattice/multi quantum well and nanodot structures [1][2][3][4]. These artificial materials offer a broadening of the functionality of optoelectronic devices [5]. Especially three dimensional (3D) ordered crystalline nanodot structures could have potential to improve device performance such as quantum dot lasers [6,7].…”

Section: Introductionmentioning

confidence: 99%

Alignment control of self-ordered three dimensional SiGe nanodots

Yamamoto

Itoh

Zaumseil

et al. 2018

Semicond. Sci. Technol.

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Alignment control of three dimensional (3D) SiGe nanodot arrangements is investigated using a reduced pressure chemical vapor deposition system. Several cycles of SiGe layers with 30% Ge content and Si spacers are deposited by SiH 4 -GeH 4 at 550 °C and SiH 4 or SiH 2 Cl 2 at 700 °C, respectively, to form a 3D SiGe nanodot structure. By using SiH 4 as a precursor for the Si spacer deposition, SiGe nanodots are aligned at staggered positions resulting in a body-centered tetragonal (BCT) structure, because a checkerboard mesa structured Si surface is formed and the next SiGe nanodot formation occurs at the concave region to reduce surface energy. On the other hand, after planarizing the Si surface with checkerboard structure by chemical mechanical polishing (CMP), the new SiGe nanodot formation occurs directly above the embedded SiGe nanodot located nearest to the Si surface (dot-on-dot). The driving force seems to be local tensile strain formed at the Si surface above the embedded SiGe nanodot. By using SiH 2 Cl 2 as precursor for the Si spacer deposition, a smooth Si surface can be realized on BCT SiGe nanodot structures without CMP process resulting in a vertically aligned SiGe nanodot formation. The local tensile strain formation in Si above SiGe nanodots is confirmed by nano beam diffraction analysis.

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“…Technologies of group IV semiconductor fabrication enable new artificial materials such as superlattice and nanodot structures (1)(2)(3). In particular, three dimensional (3D) ordered SiGe or Ge structures are promising materials to improve quantum dot lasers that can be integrated into existing CMOS platforms (4).…”

Section: Introductionmentioning

confidence: 99%

Self-Ordered Ge Nanodot Fabrication by Reduced Pressure Chemical Vapor Deposition

et al. 2018

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Ge nanodot formation on Si surface and its three dimensional alignment is investigated using a reduced pressure chemical vapor deposition (RPCVD) system. By exposing GeH4 on Si (001) surface at 550oC, a smooth wetting Ge layer is deposited for the first ~0.9 nm, and then Ge nanodot formation occurs as Stranski-Krastanov growth mechanism. The Ge nanodots are randomly distributed with density of ~6×1010 cm-2. By postannealing at 600oC, the Ge nanodots are coalesced. The size and density become ~60 nm diameter 5 nm height and ~1.5×1010 cm-2, respectively. By exposing GeH4 followed by postannealing at 600oC on checkerboard mesa structured Si surface which is fabricated by embedded body-centered tetragonal (BCT) Si0.6Ge0.4 nanodot, the Ge nanodot formation occurs at concave regions of the checkerboard mesa. By repeating Ge nanodot deposition and Si spacer deposition by two step epitaxy using SiH4 at 600oC and using SiH2Cl2 at 700oC, vertical alignment of the Ge nanodots is observed. The lateral periodicity of the Ge nanodots is the same as that of the BCT Si0.6Ge0.4 nanodot template. The driving force of the self-ordered alignment is tensile strain of Si spacer surface above the Ge nanodots.

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Novel Si–Ge–C superlattices and their applications

Cited by 7 publications

References 25 publications

Vertical alignment control of self-ordered multilayered Ge nanodots on SiGe

Vertical alignment control of self-ordered multilayered Ge nanodots on SiGe

Alignment control of self-ordered three dimensional SiGe nanodots

Self-Ordered Ge Nanodot Fabrication by Reduced Pressure Chemical Vapor Deposition

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