Using first-principles calculations a study was made of the effect of Al addition on

the diffusion of interstitial oxygen atoms and ions in HfO2. Calculated results

showed that interstitial oxygen ions in the singly negatively charged state easily

diffuse in HfO2 via exchange with lattice oxygen atoms, due to the lower diffusion

barrier as compared to those for neutral interstitial oxygen atoms and interstitial

oxygen ions in the doubly negatively charged state. The addition of Al raises the

diffusion barrier for interstitial oxygen because the interstitial oxygen was strongly

attracted by its neighbouring Al atoms. The electronic structure analysis further

revealed that the bonding between interstitial oxygen and lattice oxygen atoms was

strengthened for each charge state of interstitial oxygen in HfO2 with the addition

of Al.

Al-Induced Reduction of the Oxygen Diffusion in HfO2: an Ab Initio Study.

Z.F.Hou, X.G.Gong, Q.Li: Journal of Physics - Condensed Matter, 2008, 20[13],

135206