First-principles study of chlorine atom diffusion on Si(111)-5 x 5 reconstructed surfaces

Diffusion mechanisms of Cl atom adsorbed on Si(111)-(5 x 5) reconstructed surfaces are investigated by means of the first-principles density functional calculations. We compare two diffusion models for Cl diffusion; one is simple atom hopping model and the other is SiCl complex diffusion one, which is originally proposed to explain the diffusion process for another halogen, F. The energy barrier for the former model is calculated to be 1.73 eV, while that of the latter is 1.34 eV. This means that the complex diffusion model is preferred for Cl diffusion, similarly to the F case. It is expected that the enhancement of the diffusion frequency by the additional deposition of Si atoms found for F diffusion would be found even for Cl diffusion. (C) 2012 Elsevier B. V. All rights reserved.