Shape transitions and island nucleation for Si/Ge molecular beam epitaxy on stripe-patterned Si (001) substrate

Sanduijav, B.; Matei, Dan; Chen, G.; Springholz, G.

doi:10.1103/physrevb.80.125329

Cited by 23 publications

(24 citation statements)

References 69 publications

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“…The in-plane texture of the annealed films was investigated by means of both the azimuthal φ dependence of the distribution of surface slopes m [stereographic plots in texture (termed there as the surface orientation map, SOM) in nanostructured systems 16,17 and polycrystalline films 18 at space scales far below the DRX lateral resolution limit. Details concerning AFM image processing to compute N(m, φ) are reported elsewhere.…”

Section: Resultsmentioning

confidence: 99%

Morphology evolution of thermally annealed polycrystalline thin films

et al. 2011

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Investigation of the morphology evolution of annealed polycrystalline Au(111) films by atomic force microscopy and x-ray diffraction leads to a continuous model that correlates such an evolution to local interactions between grains triggering different mechanisms of stress accommodation (grain zipping and shear strain) and relaxation (gap filling and grain rotation). The model takes into consideration findings concerning the in-plane reorientation of the grains during the coalescence to provide a comprehensive picture of the grain-size dependence of the interactions (underlying the origin of the growth stress in polycrystalline systems); and in particular it sheds light on the postcoalescence compressive stress as a consequence of the kinetic limitations for the reorientation of larger surface structures.

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Section: Resultsmentioning

confidence: 99%

Morphology evolution of thermally annealed polycrystalline thin films

et al. 2011

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“…(Color online) Stability of perfect faceting with respect to a flat wetting layer as a function of the Ge deposition estimated through Eq. (8). Central curve is for R = 370 meV/Å, the external ones for a variation of ±10% of this value.…”

Section: Surface Energy Of Shallow Ge Nanostructures On Si In Thementioning

confidence: 99%

Stability of Ge on Si (1 1 10) surfaces and the role of dimer tilting

2012

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Using both density functional theory-local density approximation and Tersoff potentials, we calculate (1 1 10), (105), and (001) surface energies relevant to the self-assembly of Ge {105} ripples on Si (1 1 10) substrates. Surface energies are calculated as a function of Ge overlayer thickness and applied strain. Comparison of density functional theory (DFT) and Tersoff potential results reveals qualitative differences in the predicted dependence of surface energies on Ge overlayer thickness and the stability of the Ge on Si (1 1 10) surface relative to the Ge on Si (001) surface. DFT calculations show that γ (1110) Ge/Si is strongly influenced by the presence of tilted dimers, and provide an explanation for the differing stability predictions. Finally, a multiscale model including strain-and thickness-dependent γ Ge/Si is used to show that surface energy is a driving force for formation of Ge {105} ripples on Si (1 1 10), supporting recent experimental results of Ge-deposition-induced {105} faceting on Si (1 1 10).

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“…The rib section is 400 nm in bottom width and 84 nm in top width. In this idealized case, the two side walls of the Si rib are also fully decorated with one monolayer of Ge adatoms, and thus form continuous {1 0 5} facets with the Ge nanowires sitting at the rib shoulder, as observed in this and previous papers [19]. As discussed later herein, the energetic contribution from the Si rib is not taken into consideration.…”

Section: Resultsmentioning

confidence: 88%

“…Although this idea was suggested by Tersoff and Tromp two decades ago [13], its feasibility has been fully realized only recently with comprehensive studies on self-assembled Ge or SiGe nanowires on miscut Si (0 0 1) substrates [14,15], especially on the Si(1 1 10) surface [16][17][18][19][20][21][22], which is tilted off the (0 0 1) surface by 8.03°toward the 1 1 0 direction The mechanism behind wire formation and their stability on Si(1 1 10) are attributed to the abnormal faceting of the wetting layer, which is driven by the low surface energy of their {1 0 5} side facets [22]. Similar nanostructures have also been achieved on the Si (0 0 1) surface, either by template patterning [23], or by extended thermal annealing of Ge hut clusters at low temperatures [24].…”

Section: Introductionmentioning

confidence: 99%

“…Since the Ge nanowires result from faceting of the Ge wetting layer on Si (1 1 10), the whole surface is covered by them. Their length is limited by interruptions and bifurcations [17,19], which make it difficult to define and to access a specified group of nanowires with reasonable uniformity in length, width, and straightness. In this work, we have applied the strategy of template patterning to achieve a self-alignment and self-elongation of such Ge nanowires on the top of ribs etched into the Si (1 1 10) substrates along the [5 51] direction.…”

Section: Introductionmentioning

confidence: 99%

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Self-assembled in-plane Ge nanowires on rib-patterned Si (1 1 10) templates

Scopece

Springholz

et al. 2014

Phys. Rev. B

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Ge heteroepitaxy on Si (1 1 10) substrates induces the formation of prism-shaped in-plane nanowires bounded with {1 0 5} facets. In this work, in-plane nanowires were fabricated via the growth of Ge onto rib-patterned Si (1 1 10) templates oriented in the [551] direction. Atomic force microscopy (AFM) reveals that a self-elongation of the nanowires occurs, resembling the phenomena observed on rib-patterned Si (0 0 1) templates, which indicates that this is a universal effect for nanowires grown on rib patterns. Finite-element simulations, performed with input from the latest ab initio calculations, reveal that the mechanism behind these phenomena is the minimization of the total energy density of the epilayer under rib-dominated geometry. Ge surface diffusion leads to a broadening of the Ge nanowires at the rib shoulder sites, which is proved to be an effective route to reduce the total energy density. Our results provide a straightforward solution for the realization of a single or a few Ge nanowires for potential device applications.

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Shape transitions and island nucleation for Si/Ge molecular beam epitaxy on stripe-patterned Si (001) substrate

Cited by 23 publications

References 69 publications

Morphology evolution of thermally annealed polycrystalline thin films

Morphology evolution of thermally annealed polycrystalline thin films

Stability of Ge on Si (1 1 10) surfaces and the role of dimer tilting

Self-assembled in-plane Ge nanowires on rib-patterned Si (1 1 10) templates

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