In order to remove irradiation damage and achieve the exact target resistivity

the annealing technology is usually used for NTDFZSi at 750～850℃- 2h.It is found in practice that the resistivrty of NTDFZSi annealed with normal technology decreases about 10%～30% by annealing above 1150℃-5h.The results indicate that the excess carriers are generated in NTDFZSi for the annealing temperature above 1150℃.In this paper

the generation mechanism of excess carriers has been investigated

and the relationship between the excess carriers and the irradiation flux

quality of asgrown FZSi has been discussed.The experimental results show that the concentration of excess carriers increase when the concentration of as-grown micro-defects and irradiation flux are high.We think that the excess carriers are generated from the lattice damage defects caused by the neutron irradiation

and may be affected by the as-grown defects of FZSi.