Electrical analysis of niobium oxide thin films

Abstract

In this work, a series of niobium oxide thin films was deposited by reactive magnetron sputtering. The total pressure of Ar/O2 was kept constant at 1Pa, while the O2 partial pressure was varied up to 0.2Pa. The depositions were performed in a grounded and non-intentionally heated substrate, resulting in as-deposited amorphous thin films. Raman spectroscopy confirmed the absence of crystallinity. Dielectric measurements as a function of frequency (40Hz–110MHz) and temperature (100K–360K) were performed.The dielectric constant for the film samples with thickness (d) lower than 650nm decreases with the decrease of d. The same behaviour was observed for the conductivity. These results show a dependence of the dielectric permittivity with the thin film thickness. The electrical behaviour was also related with the oxygen partial pressure, whose increment promotes an increase of the Nb2O5 stoichiometry units.