Detector grade n-type float-zone Si irradiated with 140MeV O6+ ions to a dose of 5 x 1015/cm2 was studied by positron annihilation spectroscopy. Vacancy clusters containing five vacancies were detected in the irradiated sample. Isochronal annealing studies of the irradiated sample revealed the dissociation of five-vacancy clusters and formation of vacancy agglomerates V3, V6 and vacancy–O complexes at 250 to 500C. The vacancy–O complexes dissociate at 550C and released vacancies agglomerate around 600C to form voids comprising 10 vacancies. At 600 to 700C, the voids dissociate and around 750C advanced vacancy–O complexes VmOn (n>m) form.

Positron Annihilation Studies of Detector Grade n-Type Silicon Irradiated with 140MeV Oxygen (O6+) Ions. S.K.Chaudhuri, S.Mukherjee, P.V.Rajesh, S.S.Ghugre, D.Das: Physica B, 2005, 362[1-4], 249-54