A study was made of proton diffusion in amorphous SiO2 and hafnium silicates at the atomic scale. In amorphous SiO2, ab initio molecular dynamics suggested that the predominant atomic process consisted of cross-ring inter-oxygen hopping, assisted by network vibrations. In hafnium silicates, it was found that the proton localized on O atoms bonded to Hf atoms, in accord with static total-energy calculations. The results implied that, in stacked gate oxides, the proton preferentially localized within the high-κ oxide rather than within the SiO2 interlayer.

Proton Diffusion in Amorphous SiO2 and Hafnium Silicate by ab initio Molecular Dynamics. Godet, J., Pasquarello, A.: AIP Conference Proceedings, 2007, 893, 195-6