Dimer and String Formation during Low Temperature Silicon Deposition on Si(100)

Smith, Arthur P.; Jónsson, Hannes

doi:10.1103/physrevlett.77.1326

Cited by 55 publications

(52 citation statements)

References 23 publications

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“…This observation is in qualitative agreement with the theoretical predictions of Ref. [9]. Our model has one free parameter to relate with the experimental time scale; by setting up this parameter we are able to estimate the effective surface friction.…”

Section: ͑11͒supporting

confidence: 90%

“…For example, in the area of microelectronic devices there is a particular interest to understand the elementary processes involved in the homoepitaxial silicon crystal growth [5][6][7][8][9][10][11]. A particular case of this growth is the diffusion of small Si 2 molecules on a Si surface.…”

mentioning

confidence: 99%

“…STM variable temperature experiments [8] indicate a preferential direction. The activation barrier for different dimer orientations can be estimated from experimental measurements [1,7] and it has been theoretically determined by ab initio calculations [9,11]. Basically, there are two more favorable configurations which are parallel or perpendicular to the dimer surface reconstruction (crystal ͓110͔ orientation).…”

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confidence: 99%

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Modelization of surface diffusion of a molecular dimer

2004

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A simple model for a dimer molecular diffusion on a crystalline surface, as a function of temperature, is presented. The dimer is formed by two particles coupled by a quadratic potential. The dimer diffusion is modeled by an overdamped Langevin equation in the presence of a two-dimensional periodic potential. Numerical simulation's results exhibit some dynamical properties observed, for example, in Si 2 diffusion on a silicon ͓100͔ surface. They can be used to predict the value of the effective friction parameter. Comparison between our model and experimental measurements is presented. Molecular diffusion is one of the typical examples in transport phenomena where the crossing of a potential barrier is the main physical mechanism. The way a dimer is physisorbed or chemisorbed on a surface affects its diffusive motion. Experimental studies by using scanning tunneling microscope (STM) of dimer diffusion on a crystalline surface show a very rich phenomenology [1]. The understanding of the diversity of diffusion mechanisms is a challenging problem with important implications in fields such as heteroepitaxial crystal growth, chemical etching, chemical vapor deposition, and chemical surface absorption. A molecule can explore a surface by jumping potential barriers and partially governing the absorption. Our aim here is to study the diffusive aspects of this dynamical process by means of a simple statistical model within experimental scales.The last few years have witnessed an increasing interest in molecular diffusion due to the development of more sophisticated experimental setups which are able to follow the molecule path during diffusion [2][3][4]. For example, in the area of microelectronic devices there is a particular interest to understand the elementary processes involved in the homoepitaxial silicon crystal growth [5][6][7][8][9][10][11]. A particular case of this growth is the diffusion of small Si 2 molecules on a Si surface. The Si͓100͔ surface reconstructs in dimer rows with different characteristic lengths. Due to this surface anisotropy, dimer diffusion can adopt many different configurations. STM variable temperature experiments [8] indicate a preferential direction. The activation barrier for different dimer orientations can be estimated from experimental measurements [1,7] and it has been theoretically determined by ab initio calculations [9,11]. Basically, there are two more favorable configurations which are parallel or perpendicular to the dimer surface reconstruction (crystal ͓110͔ orientation). At finite temperatures the deposited dimers are able to diffuse and interchange between these two principal orientations as observed by STM [1,7].Due to the importance of the silicon diffusion, we have applied our model to this physical system. However, there are many other examples where molecule diffusion is also important, like in large molecules on metallic surfaces , etc. We think that these cases can also be rationalized using the same procedure we discuss below.In order to understand the behavior o...

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confidence: 90%

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confidence: 99%

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confidence: 99%

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Modelization of surface diffusion of a molecular dimer

2004

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“…Te is also known to be an excellent surfactant in the growth of GaAs(0 0 1) [14]. However, the detailed surfactant mechanism is not understood in either situation [9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Finite temperature studies of Te adsorption on

Sen¹,

Çiraci²,

Batra³

et al. 2002

Surface Science

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We perform first principles density functional calculations to investigate the adsorption of Te on the Si(0 0 1) surface from low coverage up to a monolayer coverage. At low coverage, a Te atom is adsorbed on top of the Si surface dimer bond. At higher coverages, Te atoms adsorption causes the Si-Si dimer bond to break, lifting the (2 Â 1) reconstruction. We find no evidence of the Te-Te dimer bond formation as a possible source of the (2 Â 1) reconstruction at a monolayer coverage. Finite temperature ab initio molecular dynamics calculations show that Te covered Si(0 0 1) surfaces do not have any definitive reconstruction. Vibrations of the bridged Te atoms in the strongly anharmonic potentials prevent the reconstruction structure from attaining any permanent, two-dimensional periodic geometry. This explains why experiments attempting to find a definite model for the reconstruction reached conflicting conclusions.

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“…At low enough temperatures, however, the situation gets more complex since kinetics forces the creation of metastable diluted dimer structures. 7,[9][10][11] Reconstructions at semiconductor surfaces are not only critical in flat-film growth but also in determining threedimensional island stability. It has been shown that a complex, rebonded-step ͑RS͒ reconstruction takes place at Ge ͕105͖ pyramid facets, 12,13 and that such a reconstruction plays a fundamental role in lowering the energy of the threedimensional islands.…”

Section: Introductionmentioning

confidence: 99%

Atomic-scale modeling of next-layer nucleation and step flow at the Ge(105) rebonded-step surface

Cereda

Montalenti

2007

Phys. Rev. B

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Based on ab initio calculations, we propose an atomic-scale path leading to the growth of a new layer on the rebonded-step reconstructed Ge͑105͒ surface. We show that the nucleation of ͑001͒-like dimers triggers the formation of low-energy adtrimers within the surface unit cell. The presence of adjacent trimers and the arrival of a further adatom initiate a fast kinetic process, allowing the perfect rebonded-step structure to be rebuilt. After repeating some of the calculations under compressive-strain conditions, we discuss position-dependent nucleation in ͑105͒ Ge pyramid on Si͑001͒, finding solid theoretical justification for the experimentally observed preferential nucleation at the top of Ge islands, followed by fast step flow.

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Dimer and String Formation during Low Temperature Silicon Deposition on Si(100)

Cited by 55 publications

References 23 publications

Modelization of surface diffusion of a molecular dimer

Modelization of surface diffusion of a molecular dimer

Finite temperature studies of Te adsorption on

Atomic-scale modeling of next-layer nucleation and step flow at the Ge(105) rebonded-step surface

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