Reliability driven guideline for BEOL Optimization: Protecting MOS stacks from hydrogen-related impurity penetration

This paper reviews our recent experiments that correlate the F-N stress-induced gate dielectric degradation with the hydrogen-related (H) species permeability of the liner nitride (SiN) film. The H permeability of SiN films was found to depend on the deposition process and the post-deposition treatment. A specific ultrathin oxynitride in the near surface region of N₂-annealed SiN films was discovered, which has the potential to function as an H-diffusion barrier. Adopting SiN films that effectively block the H-related impurity penetration is a promising route to improve the reliability of dielectrics film applied for FLASH memories.