Cyclic Growth of Strain-Relaxed Islands

LeGoues, F. K.; Reuter, M. C.; Tersoff, J.; Hammar, Mattias; Tromp, R. M.

doi:10.1103/physrevlett.73.300

Cited by 222 publications

(119 citation statements)

References 11 publications

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“…13 Moreover, islands were observed to undergo plastic relaxation, 14 causing a peculiar cyclic-growth mode. 15 Even neglecting the above effects, valid close to the onset of SK growth where intermixing is limited and island volumes are too small for dislocation nucleation, island stability is not determined solely by the volume. Indeed, it has been shown that the energetics of the WL is strongly thickness dependent up to a Ge coverage ͑⌰ Ge ͒ of 4-5 ML.…”

Section: Introductionmentioning

confidence: 99%

Key role of the wetting layer in revealing the hidden path of Ge/Si(001) Stranski-Krastanow growth onset

et al. 2009

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The commonly accepted Stranski-Krastanow model, according to which island formation occurs on top of a wetting layer ͑WL͒ of a certain thickness, predicts for the morphological evolution an increasing island aspect ratio with volume. We report on an apparent violation of this thermodynamic understanding of island growth with deposition. In order to investigate the actual onset of three-dimensional islanding and the critical WL thickness in the Ge/Si͑001͒ system, a key issue is controlling the Ge deposition with extremely high resolution ͓0.025 monolayer ͑ML͔͒. Atomic force microscopy and photoluminescence measurements on samples covering the deposition range 1.75-6.1 ML, taken along a Ge deposition gradient on 4 in. Si substrates and at different growth temperatures ͑T g ͒, surprisingly reveal that for T g Ͼ 675°C steeper multifaceted domes apparently nucleate prior to shallow ͕105͖-faceted pyramids, in a narrow commonly overlooked deposition range. The puzzling experimental findings are explained by a quantitative modeling of the total energy with deposition. We accurately matched ab initio calculations of layer and surface energies to finite-element method simulations of the elastic energy in islands, in order to compare the thermodynamic stability of different island shapes with respect to an increasing WL thickness. Close agreement between modeling and experiments is found, pointing out that the sizeable progressive lowering of the surface energy in the first few MLs of the WL reverts the common understanding of the SK growth onset. Strong similarities between islanding in SiGe and III/V systems are highlighted.

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Section: Introductionmentioning

confidence: 99%

Key role of the wetting layer in revealing the hidden path of Ge/Si(001) Stranski-Krastanow growth onset

et al. 2009

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“…The regions where a MD has been inserted are stress free and thus are preferential sites for Ge attachment [47,48,70]. In our case we suggest that this mechanism drives the morphological evolution of the islands from coherent to dislocated during annealing.…”

Section: Ge/si(111): Effects Of Sample Annealingmentioning

confidence: 59%

“…With simple geometrical analysis, Liao et al [69] assume that Si missing from the trenches has gone into alloying within the islands. Seifert et al [67] have justified the formation of trenches by using a simple model for the local strain energy density: on the WL a compressive area forms around an island, in which the strain energy difference (measured with respect to that of the WL far from the island) is large and positive, while inside the island it is negative [70]. This strain energy gradient is the driving force for the atom current from the WL towards the island [71,72], eroding the substrate that is supposed to be supercritically thick.…”

Section: Ge á/Si: Erosion Versus Intermixingmentioning

confidence: 99%

Controlling the quantum dot nucleation site

Motta

Sgarlata

Rosei

et al. 2003

Materials Science and Engineering: B

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“…At this stage, the AR vs. volume curve suddenly changes, almost assuming the form of a plateau [21,22]. A close inspection of the island shape reveals fascinating oscillations [23]. Interestingly, shape oscillations were also obtained in the absence of dislocations, as due to intermixing [24].…”

Section: Introductionmentioning

confidence: 92%

“…The growth of thick films at low temperature and high deposition rate typically does not lead to misfit strain relaxation by 3D islands but via the formation of dislocation networks [191][192][193]. Even when islands are first formed, dislocations are found to appear inside those with large volumes [21][22][23]25], partially releasing the residual misfit strain not relaxed by elasticity.…”

Section: Dislocationsmentioning

confidence: 99%

Continuum modelling of semiconductor heteroepitaxy: an applied perspective

Bergamaschini

Salvalaglio

Backofen

et al. 2016

Advances in Physics: X

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Semiconductor heteroepitaxy involves a wealth of qualitatively different, competing phenomena. Examples include threedimensional island formation, injection of dislocations, mixing between film and substrate atoms. Their relative importance depends on the specific growth conditions, giving rise to a very complex scenario. The need for an optimal control over heteroepitaxial films and/or nanostructures is widespread: semiconductor epitaxy by molecular beam epitaxy or chemical vapour deposition is nowadays exploited also in industrial environments. Simulation models can be precious in limiting the parameter space to be sampled while aiming at films/nanostructures with the desired properties. In order to be appealing (and useful) to an applied audience, such models must yield predictions directly comparable with experimental data. This implies matching typical time scales and sizes, while offering a satisfactory description of the main physical driving forces. It is the aim of the present review to show that continuum models of semiconductor heteroepitaxy evolved significantly, providing a promising tool (even a working tool, in some cases) to comply with the above requirements. Several examples, spanning from the nanometre to the micron scale, are illustrated. Current limitations and future research directions are also discussed.

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Cyclic Growth of Strain-Relaxed Islands

Cited by 222 publications

References 11 publications

Key role of the wetting layer in revealing the hidden path of Ge/Si(001) Stranski-Krastanow growth onset

Key role of the wetting layer in revealing the hidden path of Ge/Si(001) Stranski-Krastanow growth onset

Controlling the quantum dot nucleation site

Continuum modelling of semiconductor heteroepitaxy: an applied perspective

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