Scanning tunneling microscopy study of diffusion, growth, and coarsening of Si on Si(001)

The growth, diffusion, and coarsening of Si on Si(001) have been investigated with scanning tunneling microscopy (STM). A diffusion coefficient for Si has been determined. Anisotropy in the island shapes during epitaxy is shown to be principally a growth structure due to an anisotropic accommodation coefficient. Diffusional anisotropy is small. An ordered ‘‘diluted‐dimer’’ structure is observed at low coverages and temperatures.