Donor formation in nitrogen doped silicon

The formation behavior of donors associated with oxygen in nitrogen-doped and undoped Czochralski silicon has been investigated by means of electrical and infrared measurements at low temperatures (8 K). It is found that donors are not generated in N-doped silicon annealed at 650 °C up to 100 h. We have also studied the effect of preannealing at 450 and 1050 °C on the formation of donors in the N-doped silicon. The 450 °C preannealing enhances the formation of donors in the subsequent annealing at 650 °C, while the 1050 °C preannealing has no effect. The donor concentration increases at 650 °C with the 450 °C preannealing time. The formation of nitrogen–oxygen complexes in the N-doped silicon is believed to suppress the generation of nuclei of donors, and, consequently, the formation of donors.