We demonstrate that incorporating N in Hf-silicate films reduces B penetration through the dielectric film. By modeling the B depth profiles, we calculated the B diffusivities through Hf-silicate (HfSixOy) to be ∼2× higher than the corresponding diffusivities for Hf-silicon oxynitride (HfSixOyNz). B diffusion through grain boundaries after HfSixOy crystallization is believed to be responsible for the enhanced B diffusivity observed. Suppression of crystallization observed in HfSixOyNz films is attributed to the lower Hf content in the films and the incorporation of N. The decreased B penetration observed in HfSixOyNz is a combination of absence of grain boundaries and the fact that N blocks B diffusion by occluding diffusion pathways. The minimum temperatures for B penetration are estimated to be approximately 950 and 1050 °C for HfSixOy and HfSixOyNz, respectively.

We present a study of the penetration of B, P, and As through Hf silicate (HfSixOy) and the effect of N incorporation in Hf silicate (HfSixOyNz) on dopant penetration from doped polycrystalline silicon capping layers. The extent of penetration through Hf silicate was found to be dependent upon the thermal annealing budget for each dopant investigated as follows: B(T⩾950°C∕60s), P(T⩾1000°C∕20s), and As (T⩾1050°C∕60s). We propose that the enhanced diffusion observed for these dopants in HfSixOy, compared with that of SiO2 films, is related to grain boundary formation resulting from HfSixOy film crystallization. We also find that, as in the case of SiO2, N incorporation inhibits dopant (B, P, and As) diffusion through the Hf silicate and thus penetration into the underlying Si substrate. Only B penetration is clearly observed through HfSiON films for anneals at 1050 °C for durations of 10 s or longer. The calculated B diffusivity through the HfSixOyNz layer is D0=5.2×10−15cm2∕s.

Hafnium interdiffusion studies from hafnium silicate into silicon Appl. Phys. Lett. 79, 4192 (2001); 10.1063/1.1425466 Density difference related to humidity during dry oxidation for ultrathin silicon oxide films Density of ultradry ultrathin silicon oxide films and its correlation with reliability Rapid thermal annealing at 1000°C of (HfO 2 ) 1Ϫx (SiO 2 ) x pseudobinary alloy films deposited on Si were performed in N 2 or O 2 atmospheres. The effects on the atomic transport, structure, and composition were investigated using isotopic substitution of oxygen, high-resolution transmission electron microscopy, nuclear reaction analyses, narrow nuclear reaction resonance profiling, and grazing angle x-ray reflection.

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