Dielectric properties of dysprosium- and scandium-doped hafnium dioxide thin films

Dysprosium- and scandium-doped Hf O 2 films have been deposited by atomic-vapor deposition on Si O 2 ∕ Si substrates. Glancing-incidence x-ray diffraction demonstrates that Dy 0.10 Hf 0.90 O x and Sc 0.10 Hf 0.90 O x films show a cubic crystal structure, whereas Hf O 2 films are monoclinic. The dielectric permittivity increases strongly from 16 for Hf O 2 to 32 for Dy 0.10 Hf 0.90 O x and Sc 0.10 Hf 0.90 O x . This leads to a reduction of the leakage current in the tunneling regime by up to three orders of magnitude for constant effective oxide thickness. For thick films ( ≳ 6 nm ) , it is shown that leakage occurs via the Poole-Frenkel mechanism and that doping Hf O 2 increases leakage for constant physical oxide thickness.