Diffusional Kinetics of SiGe Dimers on Si(100) Using Atom-Tracking Scanning Tunneling Microscopy

Qin, X. R.; Swartzentruber, B. S.; Lagally, M. G.

doi:10.1103/physrevlett.85.3660

Cited by 76 publications

(46 citation statements)

References 10 publications

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“…Moreover, the amount of ad-dimers of this net downward flux can be quite large at the growth temperature of 650 o C. The activation barrier for Si ad-dimers migrating downward at D B step, E bs, is calculated to be 1.55 eV. 22 Considering that the activation barrier for Ge-Si 17 and Ge 24 ad-dimers on the dimer rows is smaller by about 0.1 eV and 0.3 eV than that for Si ad-dimers 18 , a simple estimate of the activation barrier at D B for Ge-Si and Ge ad-dimers yields 1.45 and 1.25 eV, respectively. The hopping-down rates of Ge-Si and Ge ad-dimers at D B steps are then estimated to be 1.2x10 5 and 1.5x10 6 /s by replacing E b in Eq.…”

Section: Figmentioning

confidence: 99%

Positioning of self-assembled Ge islands on stripe-patterned Si(001) substrates

Zhong

Halilovic

Mühlberger

et al. 2003

Journal of Applied Physics

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Abstract:Self-assembled Ge islands were grown on stripe-patterned Si (001) substrates by solid source molecular beam epitaxy. The surface morphology obtained by atomic force microscopy (AFM) and cross-sectional transmission electron microscopy images (TEM) shows that the Ge islands are preferentially grown at the sidewalls of pure Si stripes along [-110] direction at 650 o C or along the trenches, whereas most of the Ge islands are formed on the top terrace when the patterned stripes are covered by a strained GeSi buffer layer. Reducing the growth temperature to 600 o C results in a nucleation of Ge islands both on the top terrace and at the sidewall of pure Si stripes. A qualitative analysis, based on the growth kinetics, demonstrates that the step structure of the stripes, the external strain field and the local critical wetting layer thickness for the islands formation contribute to the preferential positioning of Ge islands on the stripes. I. INTRODUCTIONSelf-assembled quantum dots (SAQD) have become an intensive research topic not only because of their promising device applications 1 but also to understand the fundamental process of strained thin film growth. A frequently employed growth mode of a strained heteroepilayer is the so-called Stranski-Krastanow(SK) mode, where after a thin wetting layer the epilayer releases the misfit strain by 3D island formation. These straightforwardly formed islands can be small and in general dislocation-free, but random in position. Although locally laterally ordered SAQD have been observed, i.e., via the growth of a multilayer of SAQD, 2,3 or the growth of SAQD above a buried strained layer with a dislocation network, 4 or growth of SAQD on a vicinal surface with step-bunching, 5,6 these kinds of short-range ordered SAQD are not adequate for most electronic or optoelectronic device applications. 1 Recently, it was shown that the combination of lithographic etching techniques and the SK growth mode provides a potential to grow long-range spatially ordered SAQD. 7-13 Some interesting phenomena have been observed during the growth of SAQD on patterned substrates. For instance InAs SAQD can be preferentially grown either on the top terraces or at the sidewalls or at the trenches of stripe-patterned GaAs substrates. 7 The number of InAs SAQD can be adjusted by the depth of patterned holes. 8 Ge SAQD are preferentially grown at the edges of selectively grown Si mesas in etched SiO 2 windows, 9,10 while they preferentially grow at the sidewalls of pure Si stripes. 11 These phenomena were discussed from the point of view of either energetics or kinetics. However, no detailed discussion about the growth of SAQD on patterned substrates has been presented so far.It is the purpose of this paper to present a description of a growth mechanism to explain the main features of the Ge island formation on stripe-patterned Si (001) substrates. The preferential positioning of Ge SAQD grown at 650 o C on patterned pure Si stripes with different periodicity and height is analyzed from AFM im...

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Section: Figmentioning

confidence: 99%

Positioning of self-assembled Ge islands on stripe-patterned Si(001) substrates

Zhong

Halilovic

Mühlberger

et al. 2003

Journal of Applied Physics

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“…"Atom tracking" using scanning tunneling microscopes, has been used to study the diffusion of Ge adatoms and ad-dimers on a Si substrate [1][2][3]. The information about the surface kinetics extracted from these measurements provide a starting point for meaningful Kinetic Lattice Monte Carlo (KLMC) simulation studies of Ge on Si epitaxial growth.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Monte-Carlo simulations of germanium epitaxial growth on silicon

Akis

Ferry

2006

J Comput Electron

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We present Kinetic Lattice Monte Carlo (KLMC) simulations of Ge deposition onto a reconstructed Si (100) surface. In addition to the anisotropy brought on by surface reconstruction, we take into account the role of the exchange of Ge with Si atoms in the substrate and how it effects the interface between the materials. One method of controlling the resulting structures from the growth process is to use a pre-patterned substrate. We present results where the initial structure is a grid pattern. The KLMC simulations in this case yield Ge-Si stripes, that result largely from the anisotropy generated from the surface reconstruction.

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“…45 A mixed Si-Ge dimer can diffuse as a unit, or transform into a pure dimer between like atoms (Si-Si) due to atomic exchange with underlying substrate atom and can also return back to the mixed form due to re-exchange process. 44,45 Therefore, different alloy components deposited on surface may or may not diffuse independently. In the following studies we consider an effective surface mobility (or effective surface diffusivity D s ) to describe the processes of surface diffusion and decomposition in continuum approximation.…”

Section: Introductionmentioning

confidence: 99%

Epitaxial growth in dislocation-free strained alloy films: Morphological and compositional instabilities

Huang

Desai

2002

Phys. Rev. B

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The mechanisms of stability or instability in the strained alloy film growth are of intense current interest to both theorists and experimentalists. We consider dislocation-free, coherent, growing alloy films which could exhibit a morphological instability without nucleation. We investigate such strained films by developing a nonequilibrium, continuum model and by performing a linear stability analysis. The couplings of film-substrate misfit strain, compositional stress, deposition rate, and growth temperature determine the stability of film morphology as well as the surface spinodal decomposition. We consider some realistic factors of epitaxial growth, in particular the composition dependence of elastic moduli and the coupling between top surface and underlying bulk of the film. The interplay of these factors leads to new stability results. In addition to the stability diagrams both above and below the coherent spinodal temperature, we also calculate the kinetic critical thickness for the onset of instability as well as its scaling behavior with respect to misfit strain and deposition rate. We apply our results to some real growth systems and discuss the implications related to some recent experimental observations.

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Diffusional Kinetics of SiGe Dimers on Si(100) Using Atom-Tracking Scanning Tunneling Microscopy

Cited by 76 publications

References 10 publications

Positioning of self-assembled Ge islands on stripe-patterned Si(001) substrates

Positioning of self-assembled Ge islands on stripe-patterned Si(001) substrates

Kinetic Monte-Carlo simulations of germanium epitaxial growth on silicon

Epitaxial growth in dislocation-free strained alloy films: Morphological and compositional instabilities

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