Site exchange of Ge and Sb on Si(100) during surfactant-mediated epitaxial growth

The bonding geometry of Ge and Sb on Si(100) is investigated using scattered MeV ion energy distributions with transmission ion channeling. Coverage of 0.15 monolayer (ML) and 0.68 ML of Ge deposited at room temperature (RT) on Sb-terminated Si(100) are studied, both before and after annealing at 350 degrees C. We find that RT deposition of Ge for both coverages is consistent with a model of loosely bonded Ge dimers adsorbed between undisturbed Sb dimer rows. After annealing, we observe bulklike Ge underneath Sb dimers for 0.68 ML Ge. Our results are compared to several models in the literature.