Oxide thickness effect on boron diffusion in thin 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 whose concentration in the oxide changes under different processing conditions. We show that as the gate oxide is scaled below 80 Angstrom 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 Angstrom oxide, the B diffusivity at 900 degrees C would increase by a factor of 24 relative to diffusion in a 100 Angstrom oxide.