Ar + ion recoil-implantation of Cu and Ag from the Si(111)-quasi-5 × 5-Cu and [formula omitted] surfaces in the keV regime

Abstract

The concentration changes of Cu and Ag at the Cu Si(111) 3 × 3 - Ag and Si(111)-quasi-5 × 5-Cu surfaces by 5 keV Ar + ion bombardment have been measured by means of AES and RBS techniques in order to determine the cross sections for their recoil-implantation and desorption. From the obtained cross section for recoil-implantation we have evaluated the potential barrier height for recoil-implantation. It is also found that the Si(111)-quasi-5 × 5-Cu structure is easily destroyed by Ar + ion bombardment. From the results for the Cu Si(111) - 3 × 3 - Ag surface, together with the observed 3 × 3 LEED pattern, we propose a hypothesis that Ag atoms are accommodated at the top-most surface and that Cu atoms are buried at an interstitial site in the Si substrate.