Chlorine atom diffusion on Si(1 1 1)-(7×7) surface enhanced by hole injection from scanning tunneling microscope tips

Hole injection from scanning tunneling microscope (STM) tips was found to enhance diffusion of chlorine atoms on Si(1 1 1)-(7×7) surface. The sample bias dependence exhibits a broad peak centered at a sample bias, Vs≈−2.0V and the diffusion rate at the peak bias voltage depends linearly on the injected current. The effect spreads laterally along the surface over a range of ≈10 nm from the position of the tip, but not to extend beyond step edges. These facts are well interpreted by the model that holes injected primarily to a surface band peaking at Vs=−1.8 V propagate along the surface and become localized at Cl sites, leading somehow to destabilization or weakening of the bonds that results in Cl atom movements such as diffusion.