DONOR FORMATION IN NITROGEN-DOPED SILICON

The formation behavior of donors associated with oxygen in nitrogen-do ped 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 degrees C up to 100 h. We have also studied the effect of preannealin g at 450 and 1050 degrees C on the formation of donors in the N-doped silicon. The 450 degrees C preannealing enhances the formation of dono rs in the subsequent annealing at 650 degrees C, while the 1050 degree s C preannealing has no effect. The donor concentration increases at 6 50 degrees C with the 450 degrees C preannealing time. The formation o f nitrogen-oxygen complexes in the N-doped silicon is believed to supp ress the generation of nuclei of donors, and, consequently, the format ion of donors. (C) 1996 American Institute of Physics.