A study on the diffusion properties of oxygen in Al and W-doped λ-Ta2O5

The formation energy of an oxygen vacancy and the diffusion barrier of an oxygen ion have a significant impact on the operating voltage and other parameters of resistive random access memory. In this research, n-type dopants and p-type dopants were, respectively, used to make comparative research on the formation energy of the oxygen vacancy and the diffusion barrier of the oxygen ion in orthorhombic λ-Ta2O5 taking first-principles methods. The band unfolding calculation results show that the donor level and acceptor level are, respectively, formed in the bandgap after the doping of W and Al. After the doping of Al, the formation energy of the oxygen vacancy decreases as the doping concentration increases. Instead, after the doping of W, the formation energy of the oxygen vacancy only undergoes an increase of 0.2 eV, and the diffusion barrier increases first and then decreases with the increase in the concentration of the doped W. After the doping of Al and W, the diffusion barriers of oxygen ions change within the ranges of 0.3–1.6 and 0.12–1.23 eV, respectively.