Study of Ge loss during Ge condensation process

Xue, Zhongying; Di, Zengfeng; Ye, L.; Mu, Zhiqiang; Chen, D.; Wei, Xiaoran; Zhang, M.; Wang, X.

doi:10.1016/j.tsf.2013.08.122

Cited by 4 publications

(5 citation statements)

References 24 publications

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“…Different mechanisms [10][11][12][13][14][15][16], involving Ge oxidation at the Ge nanocrystal (Ge-nc)/SiO 2 interface, strong Ge thermal diffusion into the SiO 2 matrix via Ge trapping effects, were proposed, but none of them provided a complete description of the nanocavity formation process supported by observations at atomic scale. In addition, no experimental work can be found regarding the effects of these nanocavities on the inner structure of Ge-ncs, as well as their potential impact on the spatial redistribution of Ge after annealing.…”

Section: Introductionmentioning

confidence: 99%

Effect of nanocavities on Ge nanoclustering and out-diffusion in SiO₂

Feng

Liu

et al. 2016

Nanotechnology

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Germanium nanocrystals (Ge-ncs) were synthesized by implantation of Ge ions into the fused silica, followed by a thermal annealing at 1000 °C. High-resolution transmission electron microscopy was employed to characterize both the morphology of the formed Ge-ncs and the evolution of their depth-distribution as a function of annealing durations. The formation of nanocavities in the vicinity of nanocrystal/SiO interface is evidenced, as well as their influence on the release of the compressive stress exerted on Ge-ncs by surrounding SiO. Some Ge-ncs are found inside nanocavities, and can move into the implanted layer through a nanocavity-assisted diffusion mechanism. This finding sheds light on a new process that can explain the non-uniformity of the Ge-nanocrystal spatial distribution.

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Section: Introductionmentioning

confidence: 99%

Effect of nanocavities on Ge nanoclustering and out-diffusion in SiO₂

Feng

Liu

et al. 2016

Nanotechnology

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“…The Ge condensation process has been reported as a relevant method of fabricating ultrathin Ge-rich SiGe layers (GRLs) on SOI with a controlled thickness and composition. − The process takes place during dry thermal oxidation of SiGe, which consumes Si atoms to form a SiO 2 layer on top of the SiGe. In parallel, the Ge atoms pile up at this new SiGe/SiO 2 interface, forming the GRL without loss of Ge until the silicon is fully oxidized . The enrichment mechanism has been explained by the much lower formation energy of SiO 2 than GeO 2 ( E SiO 2 = −8.2 eV and E GeO 2 = −4.7 eV) which highly favors the formation of SiO 2 over GeO 2 …”

Section: Introductionmentioning

confidence: 99%

“…In parallel, the Ge atoms pile up at this new SiGe/ SiO 2 interface, forming the GRL without loss of Ge until the silicon is fully oxidized. 14 The enrichment mechanism has been explained by the much lower formation energy of SiO 2 than GeO 2 (E SiO 2 = −8.2 eV and E GeO 2 = −4.7 eV) which highly favors the formation of SiO 2 over GeO 2 . 15 A quite different mechanism was observed during lowtemperature plasma-assisted oxidation.…”

Section: ■ Introductionmentioning

confidence: 99%

Kinetics and Energetics of Ge Condensation in SiGe Oxidation

et al. 2015

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International audienceThe fabrication of an ultrathin Ge-rich SiGe body on silicon on insulator (SOI) is highly challenging for the next generation of fully depleted complementary metal-oxide semiconductor devices that will be implemented in the near future. Ge-rich layers (GRLs) could be fabricated using a Ge enrichment process which takes place during dry thermal oxidation of SiGe thin films. While several studies make use of the GRL for many applications, the basic mechanism at work during the enrichment process is still unclear. In this study, we address the mechanism of formation of GRL and we determine the major driving forces of the enrichment process. We highlight the particular role played by the Si0.5Ge0.5 which is stabilized for various experimental conditions and strain levels. A systematic study demonstrates that the 50% Ge content is stabilized by a self-limited interdiffusion process regulated by the entropic term of the formation energy, which is a minimum at Si0.5Ge0.5 at the expense of the elasticity-driven interdiffusion. The process developed provides an easy and efficient way to produce planar GRLs free of dislocations with abrupt GRL/Si interfaces and tunable thickness. These GRLs could be fashioned for the heterogeneous integration of various systems on SOI

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“…When a SiGe alloy is oxidized, the oxidation potential of Si is sufficiently greater than that of Ge such that Si is preferentially oxidized and Ge is rejected, which results in a pileup of epitaxial, single crystal SiGe at the SiO 2 /SiGe substrate interface. − During this process, a Ge rich layer is formed, which continues to increase in concentration up to a value of 36–64%, which is governed by the oxidation temperature . Once this concentration is reached, the Ge rich layer will maintain its thickness and continue to be rejected by the advancing oxide front provided there is Si below it to be oxidized and the temperature is sufficient for the Ge to diffuse into the Si. This process has been widely investigated for use in the fabrication of Ge-on-insulator (GeOI) substrates for CMOS applications. − …”

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confidence: 99%

“…17−19 During this process, a Ge rich layer is formed, which continues to increase in concentration up to a value of 36−64%, which is governed by the oxidation temperature. 20 Once this concentration is reached, the Ge rich layer will maintain its thickness and continue to be rejected by the advancing oxide front provided there is Si below it to be oxidized 21 and the temperature is sufficient for the Ge to diffuse into the Si. This process has been widely investigated for use in the fabrication of Ge-on-insulator (GeOI) substrates for CMOS applications.…”

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confidence: 99%

Lateral Ge Diffusion During Oxidation of Si/SiGe Fins

et al. 2017

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This Letter reports on the unusual diffusion behavior of Ge during oxidation of a multilayer Si/SiGe fin. It is observed that oxidation surprisingly results in the formation of vertically stacked Si nanowires encapsulated in defect free epitaxial strained SiGe. High angle annular dark field scanning transmission electron microscopy (HAADF-STEM) shows that extremely enhanced diffusion of Ge occurs along the vertical Si/SiO oxidizing interface and is responsible for the encapsulation process. Further oxidation fully encapsulates the Si layers in defect free single crystal SiGe (x up to 0.53), which results in Si nanowires with up to -2% strain. Atom probe tomography reconstructions demonstrate that the resultant nanowires run the length of the fin. We found that the oxidation temperature plays a significant role in the formation of the Si nanowires. In the process range of 800-900 °C, pure strained and rounded Si nanowires down to 2 nm in diameter can be fabricated. At lower temperatures, the Ge diffusion along the oxidizing Si/SiO interface is slow, and rounding of the nanowire does not occur, while at higher temperatures, the diffusivity of Ge into Si is sufficient to result in dilution of the pure Si nanowire with Ge. The use of highly selective etchants to remove the SiGe could provide a new pathway for the creation of highly controlled vertically stacked nanowires for gate all around transistors.

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Study of Ge loss during Ge condensation process

Cited by 4 publications

References 24 publications

Effect of nanocavities on Ge nanoclustering and out-diffusion in SiO₂

Effect of nanocavities on Ge nanoclustering and out-diffusion in SiO₂

Kinetics and Energetics of Ge Condensation in SiGe Oxidation

Lateral Ge Diffusion During Oxidation of Si/SiGe Fins

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Study of Ge loss during Ge condensation process

Cited by 4 publications

References 24 publications

Effect of nanocavities on Ge nanoclustering and out-diffusion in SiO2

Effect of nanocavities on Ge nanoclustering and out-diffusion in SiO2

Kinetics and Energetics of Ge Condensation in SiGe Oxidation

Lateral Ge Diffusion During Oxidation of Si/SiGe Fins

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Product

Resources

About

Effect of nanocavities on Ge nanoclustering and out-diffusion in SiO₂

Effect of nanocavities on Ge nanoclustering and out-diffusion in SiO₂