Halogen chemisorption, the pairwise diffusion of I, and trapping by defects on Si(100)

Xu, Gang; Signor, A. W.; Agrawal, Abhishek; Nakayama, Koji S.; Trenhaile, B. R.; Weaver, J. H.

doi:10.1016/j.susc.2004.12.026

Cited by 17 publications

(20 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Studies showed that separate adatoms in dissociative adsorption of many diatomic molecules on the clean Si͑100͒ surface are usually one or two atom units away from each other. 26,30,40 Accordingly, we first model HCl chemisorption as a process in which, upon striking on one dangling bond, one of the two separated atoms ͑referred to as the first atom A͒ is trapped and chemisorbed on the dangling bond and the second atom ͑referred to as B͒ is chemisorbed on one of the nearest or second nearest active sites ͑dissociative adsorption͒ or desorbs from the surface ͑atom abstraction͒.…”

Section: Monte Carlo Simulationsmentioning

confidence: 99%

“…39,40 Thus, the correlation between Cl adsorption sites is established during the adsorption process and before the formation of Cl-Si bonds. Hence, the partial ordering of Cl sites suggests that forces between a Cl atom ͑Cl fragment͒ and its surrounding adsorbates are already present before the chemisorption of a Cl fragment is completed.…”

Section: Simulation With the Introduction Of Fragment-adsorbate Inmentioning

confidence: 99%

See 1 more Smart Citation

Determination of dissociative fragment-adsorbate interaction energy during chemisorption of the diatomic molecule HCl on Si(100)

et al. 2010

View full text Add to dashboard Cite

This study investigates the surface chemistry and the ordering characteristics of coadsorbed hydrogen and chlorine atoms, generated by the exposure of the Si͑100͒ surface to gas-phase HCl molecules at various substrate temperatures, by scanning tunneling microscopy ͑STM͒, core-level photoemission spectroscopy, and Monte Carlo simulation. Experimental results show that saturation exposure to HCl causes all surface dangling bonds to be terminated by the two fragments H and Cl atoms and that the number of H-terminated sites exceeds that of Cl-terminated ones by more than 10%. This finding suggests that, in addition to the dominant dissociative chemisorption, atomically selective chemisorption or atom abstraction occurs. STM images reveal that some Cl-terminated sites form patches with a local 2 ϫ 2 structure at 110 K and that the degree of ordering is reduced as the substrate temperature increases. Results of Monte Carlo simulations demonstrate the importance of including dissociative fragment-adsorbate interactions during the random adsorption of diatomic molecules. Comparing the correlations between Cl-terminated sites identified from STM images and those predicted by simulation reveals two effective interaction energies of 8.5Ϯ 2.0 and 3.5Ϯ 2.0 meV between a dissociative fragment Cl atom and a nearest neighboring Cl adsorbates in the same dimer row and in the adjacent row, respectively.

show abstract

Section: Monte Carlo Simulationsmentioning

confidence: 99%

Section: Simulation With the Introduction Of Fragment-adsorbate Inmentioning

confidence: 99%

Determination of dissociative fragment-adsorbate interaction energy during chemisorption of the diatomic molecule HCl on Si(100)

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Pairing of two Cl(i) on a dimer should be favored over one per dimer [19] and hence the relatively facile diffusion should lead to formation of favorable precursors for desorption, such as 2SiCl 2 . Once paired, further diffusion would favor pairwise motion [20], conserving the volatile state. Etching then results from desorption of both SiCl 2 species to create a dimer vacancy without residual Si for regrowth.…”

mentioning

confidence: 99%

Cl Insertion onSi(100)−(2×1): Etching Under Conditions of Supersaturation

2007

Self Cite

View full text Add to dashboard Cite

We use scanning tunneling microscopy to show that Cl2 dosing of Cl-saturated Si(100)-(2x1) surfaces at elevated temperature leads to uptake beyond "saturation" and allows access to a new etching pathway. This process involves Cl insertion in Si-Si dimer bonds or backbonds, diffusion of the inserted Cl, and ultimately desorption of SiCl2. Investigations into the etch kinetics reveal that insertion occurs via a novel form of Cl2 dissociative chemisorption that is mediated by dangling bond sites. Upon dissociation, one Cl atom adsorbs at the dangling bond while the other can insert.

show abstract

“…2,3,26 The activation energies obtained here are considerably lower than those of intrarow H atomic diffusion ͑1.7 eV͒, 27,28 but higher than that ͑1.0 eV͒ of H intradimer diffusion and that ͑1.1 eV͒ of Cl diffusion on a clean Si͑100͒ surface. 29,30 Fig. 3͑b͒ plots the residence-time distributions at 550 and 590 K. The distributions do not follow very closely a form of exponential decay, suggesting a site-specific activation energies 31 and/or nonArrhenius behavior.…”

Section: Resultsmentioning

confidence: 97%

Possibility of direct exchange diffusion of hydrogen on theCl/Si(100)−2×1surface

2009

View full text Add to dashboard Cite

The diffusion behavior of hydrogen substitutional sites on the chlorine-terminated Si͑100͒ surface was investigated at elevated temperatures using time-lapse scanning tunneling microscopy ͑STM͒. STM movies show that each hydrogen atom undergoes Brownian motion within a monochloride dimer row. The position of a hydrogen substitutional site is exchanged directly with that of an immediate neighboring chlorine atom in either the same dimer ͑intradimer diffusion͒ or in one of the two adjacent dimers in the same row ͑intrarow diffusion͒. Accordingly, conceptual direct exchange diffusion ͑DED͒ in a two-dimensional lattice was experimentally observed. Analysis of STM movies at various temperatures yielded rather low attempt frequencies and energy barriers, leading to the suggestion that the diffusion mechanism involves an intermediate lowenergy molecular state. Density-functional theory ͑DFT͒ calculations were also performed and provided partial support for the proposed diffusion mechanism.

show abstract

Halogen chemisorption, the pairwise diffusion of I, and trapping by defects on Si(100)

Cited by 17 publications

References 28 publications

Determination of dissociative fragment-adsorbate interaction energy during chemisorption of the diatomic molecule HCl on Si(100)

Determination of dissociative fragment-adsorbate interaction energy during chemisorption of the diatomic molecule HCl on Si(100)

Cl Insertion onSi(100)−(2×1): Etching Under Conditions of Supersaturation

Possibility of direct exchange diffusion of hydrogen on theCl/Si(100)−2×1surface

Contact Info

Product

Resources

About