Boron penetration studies from p+ polycrystalline Si through HfSixOy

Abstract

We present detailed B penetration studies from B-doped polysilicon through alternate gate dielectric candidate HfSixOy films. No detectible B penetration is observed for annealing times as long as 20 s after 950 °C. Considerable B incorporation into the Si substrate is observed for annealing temperatures higher than 950 °C. By modeling the B depth profiles, we calculated the B diffusivities through HfSixOy to be higher than the corresponding diffusivities for SiO2. B diffusion through grain boundaries after HfSixOy crystallization is proposed to be responsible for the enhanced B diffusivity observed.