LOW-ENERGY-ION ENHANCED DIFFUSION AT THE SURFACE OF METALS

Radiation enhanced diffusion at the surface of metals has been observed and studied for low-energy nitrogen ions at the surface of copper. The displacement of the target atoms during irradiation creates vacancies and other defects near the surface, thus enhancing the diffusion of implanted materials toward the surface and also into the solid. The mechanism has been studied here by a special method. An overcoat layer has been evaporated on the surface of the thin film sample following the implantation and the defects have been produced in the overcoat layer by another ion. The original implanted ions are observed to diffuse to the new surface through the open channels created by the auxiliary ions. The effect of this diffusion on the range distributions of low-energy ions in copper has also been discussed