DAMAGE PRODUCTION AT THE SURFACE OF SI SINGLE-CRYSTALS BY 200 KEV HE+ BOMBARDMENT

Damage build-up at the surface of silicon single crystals irradiated by 200 kev He** plus was studied using the channeling technique. To investigate the role of diffusion of defects to the surface, traps were created in the bulk by doping samples with impurities (As and B) known to form complexes with point defects or by creating a buried damaged layer by N** plus implantation. In all cases the initial damage introduction rate at the surface was equal to that for undoped samples. Therefore it is concluded that for surface atom displacement the role of diffusion of defects to the surface is insignificant.