SUPPRESSION OF COBALT SILICIDE AGGLOMERATION USING NITROGEN (N-2(+)) IMPLANTATION

In this paper, the effects of nitrogen coimplantation with boron into p(+)-poly gate in PMOSFET's on the agglomeration effects of CoSi2 are studied. The thermal stability of CoSi2/poly-Si stacked layers can be significantly improved by using nitrogen implantation. Samples with 40 -nm Cobalt Silicide (CoSi2) on 210-nm poly-Si implanted by 2 x 10(15)/ cm(2) N-2(+) are thermally stable above 950 degrees C for 30 s in N-2 ambient. If the dose of nitrogen is increased up to 6 x 10(15)/cm(2), the sheet resistance of CoSi2 film is not increased at all, and TEM ph otographs show that the agglomeration of CoSi2 film is completely supp ressed.