Using first-principles calculations, a study was made of the effect of Al additions upon the diffusion of interstitial O atoms and ions in HfO2. The calculated results showed that interstitial O ions in the singly negatively charged state easily diffused in HfO2 via exchange with lattice O atoms, due to the lower diffusion barrier as compared to those for neutral interstitial O atoms and interstitial O ions in the doubly negatively charged state. The addition of Al raises the diffusion barrier for interstitial O because the interstitial O was strongly attracted by its neighboring Al atoms. The electronic structure analysis further reveals that the bonding between interstitial O and lattice O atoms was strengthened for each charge state of interstitial O 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 (5pp)