The migration of Si on Si(001) has been investigated by analyzing the number density of islands formed during deposition using scanning tunneling microscopy. The activation energy and prefactor for diffusion in the fast direction, which is along the surface dimer rows, are found to be 0.67±0.08 eV and ∼${10}^{\mathrm{-}3}$ ${\mathrm{cm}}^2$/sec, respectively.

• Received 4 February 1991

DOI:https://doi.org/10.1103/PhysRevLett.66.1998