To understand the role of dopants in the electronic properties of monoclinic hafnium dioxide, first-principles simulations were performed using density functional theory. The structure, ionization energies, electron affinities, formation energies, and activation energies for fluorine and N atoms in different charge states were obtained. Compared to N incorporation, it was observed that F introduction improved the dioxide performances more efficiently; removing the band-gap state introduced by the O vacancy. The results suggested that F was the best passivator of O vacancies and that its incorporation could be used to decrease the gate leakage current through hafnia-based devices.

Investigations of Dopants Introduction in Hafnia: Electronic Properties, Diffusion, and Their Role on the Gate Leakage Current. V.Cuny, N.Richard: Journal of Applied Physics, 2008, 104[3], 033709