Ge surface segregation at low temperature during SiGe growth by molecular beam epitaxy

Godbey, D. J.; Lill, James; Deppe, J.; Hobart, Karl D.

doi:10.1063/1.112277

Cited by 47 publications

(16 citation statements)

References 17 publications

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“…4 also shows that Ge segregation is slightly greater at 500°C than 800°C. This is in agreement with previous experimental studies [11][12][13][14][15] and with the model of Godbey and Ancona [16], where they assume exchange can occur from within the top 2-3 layers. For our measurements, the XPS signal was collected at near normal incidence and therefore was not sensitive to the surface roughness caused by the quantum dots.…”

Section: Resultssupporting

confidence: 91%

Evolution of Si0.8Ge0.2 quantum dots during Si encapsulation

Jernigan

Thompson

2006

Surface Science

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Section: Resultssupporting

confidence: 91%

Evolution of Si0.8Ge0.2 quantum dots during Si encapsulation

Jernigan

Thompson

2006

Surface Science

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“…We attribute this to changes of the surface reconstruction, 15 which affects both adatom diffusion and step-edge incorporation. Ge segregation, which is near its maximum at the growth temperatures employed, 16 explains why small volume concentrations affect the kinetics so strongly.…”

mentioning

confidence: 99%

Si1−xGexgrowth instabilities on vicinal Si(001) substrates: Kinetic vs. strain-induced effects

et al. 2001

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A comparative study of kinetically and thermodynamically driven instabilities on vicinal Si͑001͒ surfaces during overgrowth with Si 1Ϫx Ge x is reported. We mapped out a wide range of the multidimensional growth parameter space and found, in contrast to previous reports, no evidence for strain-induced step bunching. At low Ge concentrations strain is insufficient to promote strain-induced step bunching, and the modified surface kinetics in the presence of segregated Ge leads to a smoother rather than rougher morphology. High Ge concentrations around 50% could be expected to provide enough strain, but near equilibrium hut cluster formation is the more effective strain-relaxation mechanism. We found the characteristically rippled stepbunching morphology only in a kinetically limited growth regime, where strain is of limited relevance, and in experiments where the SiGe layers replicate an underlying ripple morphology.

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“…Similar surface segregation phenomena are known to occur for Si layers deposited on SiGe surfaces, where the Ge from the SiGe layer would segregate to the growing Si surface and result in Ge incorporation in the Si layer with a similar decaying concentration profile to what we observed here for Ga in depositing Ge film. [28][29][30][31] This type of segregation process has been modeled with a two-state exchange kinetics model, 31 modified from a dopant segregation exchange model. 32,33 Unlike the bulk diffusion process, surface exchange is a surface-assisted process, highly depending on the energy state of the exchange species on the surface.…”

Section: Ga Incorporation In Ge Epitaxial Layermentioning

confidence: 99%

Photoluminescence and secondary ion mass spectrometry investigation of unintentional doping in epitaxial germanium thin films grown on III-V compound by metal-organic chemical vapor deposition

Bulsara¹,

Fitzgerald²

2012

Journal of Applied Physics

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High quality epitaxial germanium (Ge) thin films grown on lattice matched and mismatched III-V compound may lead to development of new electronic and optoelectronic devices. Understanding the doping and electronic properties of these Ge thin films is the first step in this development. In this paper, we report on high-quality epitaxial Ge thin films grown on GaAs and AlAs by metal-organic chemical vapor deposition. Cross-sectional transmission electron microscopy and atomic force microscopy reveal the high structural quality of the Ge thin films. Using photoluminescence, secondary ion mass spectrometry, and spreading resistance analysis, we investigated the unintentional doping characteristics of the fabricated Ge-on-III-V thin films. We found that arsenic (n-type doping) concentration is determined by the background partial pressure of volatile As-species (e.g., As 2 and As 4 ), which incorporate into the Ge thin films via gas phase transport during the growth. Group III element (p-type doping) incorporation in the Ge thin films occurs during the growth through a surface exchange process. There exists a trade-off between Ge film structural quality and group III element "auto-doping." III-V compound surfaces that are group III element-rich facilitate the initiation of Ge thin films with high crystalline quality and low surface roughness. However, the group-III-rich surfaces also result in high group III element (p-type doping) concentrations in the Ge thin films.

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Ge surface segregation at low temperature during SiGe growth by molecular beam epitaxy

Cited by 47 publications

References 17 publications

Evolution of Si0.8Ge0.2 quantum dots during Si encapsulation

Evolution of Si0.8Ge0.2 quantum dots during Si encapsulation

Si1−xGexgrowth instabilities on vicinal Si(001) substrates: Kinetic vs. strain-induced effects

Photoluminescence and secondary ion mass spectrometry investigation of unintentional doping in epitaxial germanium thin films grown on III-V compound by metal-organic chemical vapor deposition

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