PARAMAGNETIC DEFECTS IN SILICON IRRADIATED WITH 40 MEV AS IONS

The structure and the depth distribution of paramagnetic defects in n- and p-type silicon irradiated with 40 MeV As ions at doses in the ran ge 1-7x10(14) cm-2 were investigated by the use of the EPR technique. The tetravacancies (spectrum P3) and VV-like centers (g congruent-to 2 .0055) were found to dominate after such an irradiation. The depth dis tribution of the observed defects is characterized by a sharp peak due to the W-like centers concentration near the end of this high-energy ion range (R(p) congruent-to 10 mum) and a relatively broad peak of th e tetravacancies concentration at a depth of d congruent-to 5 mum. The VV-like centers linewidth was found to be dependent on the magnetic f ield orientation, irradiation dose and the depth of these centers. All the obtained data are analyzed in terms of the production and overlap of damaged regions along the ion track and the influence of ion-stimu lated self-annealing of defects at the subsurface region (d = 0-5 mum) , where the electronic stopping power (dE/dR)e is too high.