Ultrathin
(normalNb1−xnormalTax)2normalO5
films, with thicknesses from
∼3to∼25nm
, 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
normalNb2normalO5
. With increasing Nb content, increasing leakage currents were observed. The crystallization temperature was determined by in situ X-ray diffraction measurement for films with
∼15nm
thickness:
normalNb2normalO5
was crystalline as deposited
(600°C)
, while the crystallization temperature of solid solutions increased with increasing Ta content, up to
875°C
for pure
normalTa2normalO5
.
NbTanormalO5
showed a marked increase in permittivity from 27 to 38 after crystallization anneal at 600 and
800°C
, respectively. For
normalNb2normalO5
, no significant difference in permittivity was observed between amorphous and crystalline layers.