Papers Published

1. Fair, R.B., Boron diffusion in ultrathin silicon dioxide layers, Proceedings of the Third International Symposium on the Physics and Chemistry of SiO₂ and the Si-SiO₂ Interface. The Physics and Chemistry of SiO₂ and the Si-SiO₂ Interface - 3 1996 (1996), pp. 200 - 13 .
   (last updated on 2007/04/17)

   Abstract:
   Based on a network defect model for the diffusion of B in SiO₂, we propose that B diffuses via a peroxy linkage defect whose concentration in the oxide changes under different processing conditions. We show that as the gate oxide is scaled below 80 Å in thickness, additional chemical processes act to increase B diffusivity and decrease its activation energy, both as a function of the distance from the Si/SiO₂ interface. For a 15 Å oxide, the B diffusivity at 900°C would increase by a factor of 24 relative to diffusion in a 100 Å oxide. The role of nitridation of SiO₂ to create a barrier to B diffusion is modeled by assuming the N atoms compete with B for occupation of diffusion-defect sites. The model predicts that nitridation is ineffective in stopping B penetration when BF₂ implants are used to dope the polysilicon gate, and for the case of very thin gate dielectrics

   Keywords:
   boron;diffusion;silicon compounds;