Dopant boron concentration dependence on electron irradiation enhanced defects in Czochralski silicon

Abstract Positron annihilation lifetime experiments have been performed for CZ-Si with B concentration ranging over 8.3×10 17 –2.5×10 20 /cm 3 irradiated with 6 MeV electrons at room temperature. The mean lifetimes were hardly changed in the specimens with B below 8.0×10 18 /cm 3 , and increased in the specimen above 8.6×10 19 /cm 3 by irradiation. No remarkable lifetime change with B concentration was obtained with the increase of electron fluence up to 5×10 15  e/cm 2 , and the mean lifetimes of the specimens with B more than 8.6×10 19 /cm 3 increased with electron fluences higher than 1×10 16  e/cm 2 . It is concluded that complex defect clusters of B x O y V z are formed by electron irradiation, which have shorter positron lifetimes than the bulk.