Positron annihilation study of dopant effects on proton-irradiation defectin silicon

Positron annihilation lifetime and doppler broadening measurements have bee n performed to examine the effects of B, Al and Ga dopants of Czochralski-g rown Si (CZ-Si) on defects induced by 10 MeV proton irradiations at room te mperature with a total dose from 3 x 10(12) p/cm(2) to 5 x 10(14) p/cm(2). Isochronal annealing experiments were also carried out after the irradiatio ns. In spite of the high-energy proton irradiation, a short lifetime compon ent tau(1) of about 100 ps was observed in all of the specimens, which is c onsidered to be responsible for dopant-oxygen-vacancy complexes. The long l ifetime component becomes remarkable in specimens with irradiation more tha n 10(14) p/cm(2). In isochronal annealing experiments, annealing stages at 527 and 552 K were observed for the irradiated B doped CZ-Si with resistivi ties of 10 and 2 Omega cm, respectively. This corresponds to the formation of larger vacancy clusters. We found that the formation of the vacancy-oxyg en complex depends on the species of dopant atoms of silicon, especially at irradiation below 10(14) p/cm(2). (C) 1999 Elsevier Science B.V. All right s reserved.