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

Abstract

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.

Charge-Transfer in Silicon Governs the Pattern of Dissociative Attachment of Hydrogen Halides: HCl, HBr, and HI

“…Earlier experiments of HCl and HBr on Si(100) were performedin contrast to the present workat saturation coverage − or on a hydrogenated surface . While dissociative attachment was found to be a major pathway, previous authors found evidence of the abstraction of single atoms, H or Cl, by the surface.…”

AlCl3-Dosed Si(100)-2 × 1: Adsorbates, Chlorinated Al Chains, and Incorporated Al

“…While there are other gaseous constituents in the chamber during dosing that could contribute to these features, those are predominantly Ar and H 2 (low sticking coefficient) as well as HCl, which does not appear to be present in significant amounts on our dosed surfaces. HCl appears in STM as small, alternating round features that we have observed when the Ar is removed from the AlCl 3 bottle before dosing (see Figure S2 in the Supporting Information). However, as stated before, Ar was left in the bottle for these experiments, mitigating HCl generation.…”

Kinetic Model of SiGe Selective Epitaxial Growth using RPCVD Technique

“…The etching of Cl atoms have been previously studied and reported by many groups. [29][30][31][32][33] But, Eq. 11 represents Cl etch during the epitaxy growth, which differs remarkably from a simple Si vapor etching.…”