Hardy A.,Hasselt University |
Hardy A.,Interuniversity Micro Electronics Center Vzw |
Van Elshocht S.,Interuniversity Micro Electronics Center Vzw |
Dewulf D.,Hasselt University |
And 18 more authors.
Journal of the Electrochemical Society | Year: 2010
Ultrathin (Nb1-xTax)2O5 films, with thicknesses from ∼3 to ∼25 nm, were deposited by chemical solution deposition starting from aqueous precursor solutions. The film's dielectric properties were characterized by capacitance-voltage and current-voltage measurements. Permittivities ranged from 20 to 31 after annealing at 600°C, with the highest value obtained for pure Nb2O5. With increasing Nb content, increasing leakage currents were observed. The crystallization temperature was determined by in situ X-ray diffraction measurement for films with ∼15 nm thickness: Nb2O5 was crystalline as deposited (600°C), while the crystallization temperature of solid solutions increased with increasing Ta content, up to 875°C for pure Ta2O5. NbTaO5 showed a marked increase in permittivity from 27 to 38 after crystallization anneal at 600 and 800°C, respectively. For Nb2O5, no significant difference in permittivity was observed between amorphous and crystalline layers. © 2009 The Electrochemical Society.