Modeling boron diffusion in ultrathin nitrided oxide p(+) Si gate technology

Based on a network defect model for the diffusion of B in SiO2, we propose that B diffuses via a peroxy linkage defect (pld) whose concentration in the oxide changes under different processing conditions. We show that as N is added to the gate oxide (nitridation), N atoms compete with B atoms for activation through the diffusion-defect sites. The model predicts that nitridation is ineffective in stopping B penetration when BF2 implants dope the polysilicon gate, as well as for the case of very thin gate dielectrics with B-implanted gates.