Positron annihilation studies of detector grade n-type silicon irradiated with 140 MeV oxygen (O 6+) ions

Abstract

Detector grade n-type float-zone silicon irradiated with 140 MeV O 6+ ions to a dose of 5×10 15 particles/cm 2 was studied by positron annihilation spectroscopy. Vacancy clusters containing five vacancies were detected in the irradiated sample. Isochronal annealing studies of the irradiated sample reveal the dissociation of five-vacancy clusters and formation of vacancy agglomerates V 3, V 6 and vacancy–oxygen complexes in the temperature range 250–500 °C. The vacancy–oxygen complexes dissociate at 550 °C and released vacancies agglomerate around 600 °C to form voids comprising 10 vacancies. In the temperature range 600–700 °C, the voids dissociate and around 750 °C advanced vacancy–oxygen complexes V m O n ( n> m) form.