Publication

Migration of oxygen vacancy in HfO2 and across the HfO2/SiO2 interface: A first-principles investigation

Alfredo Pasquarello
2007
Journal Articles

Abstract

Oxygen vacancy migration is studied in monoclinic HfO2 and across its interface with SiO2 through density functional calculations. In HfO2, long-range diffusion shows activation barriers of 2.4 and 0.7 eV for the neutral and doubly positively charged vacancy, respectively. In the latter case, the migration preferentially occurs along one-dimensional pathways. A HfO2/SiO2 interface model is constructed to address O vacancy migration across high-kappa gate stacks. The vacancy is shown to stabilize in its neutral charge state upon entering the SiO2 layer.

Official source

https://infoscience.epfl.ch/entities/publication/3a8ec6f4-d6b0-45c7-aead-ef70e00122be

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Alfredo Pasquarello
2007
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/3a8ec6f4-d6b0-45c7-aead-ef70e00122be

About this result

Related concepts (16)

Density functional theory

Density-functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-body systems, in particular atoms, molecules, and the condensed phases. Using this theory, the properties of a many-electron system can be determined by using functionals, i.e. functions of another function. In the case of DFT, these are functionals of the spatially dependent electron density.

Electron density

Electron density or electronic density is the measure of the probability of an electron being present at an infinitesimal element of space surrounding any given point. It is a scalar quantity depending upon three spatial variables and is typically denoted as either or . The density is determined, through definition, by the normalised -electron wavefunction which itself depends upon variables ( spatial and spin coordinates). Conversely, the density determines the wave function modulo up to a phase factor, providing the formal foundation of density functional theory.

Local-density approximation

Local-density approximations (LDA) are a class of approximations to the exchange–correlation (XC) energy functional in density functional theory (DFT) that depend solely upon the value of the electronic density at each point in space (and not, for example, derivatives of the density or the Kohn–Sham orbitals). Many approaches can yield local approximations to the XC energy. However, overwhelmingly successful local approximations are those that have been derived from the homogeneous electron gas (HEG) model.