Epitaxial growth of Ag films on native-oxide-covered Si substrates

By employing radio-frequency magnetron sputtering, cube-on-cube domain epitaxy of silver films was accomplished on the Si(001) substrates that were initially covered with native silicon oxide. Energetic bombardment by sputtered Ag particles was found to play a critical role in the epitaxial growth, enabling desorption of native oxide at temperatures significantly lower than that reported in conventional thermal annealing in ultrahigh vacuum. Native oxide was found to desorb at temperatures as low as 200 degrees C as a result of kinetic interaction with the deposition flux. At deposition temperatures of 550 degrees C or above, native oxide was completely removed from the Si surface, and the grown films showed strong epitaxial relationship, Ag(001)[110]//Si(001)[110]. X-ray photoemission spectroscopy analysis confirmed that the desorbed silicon oxide migrated to the top surface of the Ag layer during sputter deposition.