ATOMIC LAYER DEPOSITION OF DIELECTRIC Nb_2O_5 FILMS USING THE NbI_5O_2 PRECURSOR COMBINATION

摘要

In the present study, thin films of niobium oxide, Mb_2O_5, were deposited by atomic layer deposition (ALD) using NbI_5 as metal precursor and O_2 as oxygen source. The films were characterised by XRFS, XPS and XRD, showing that the films consisted of Nb_2O_5 without any measurable iodine contaminations. The films were amorphous below 450 ℃, whereas crystalline films were obtained at higher deposition temperatures. Capacitance-voltage measurements revealed dielectric behaviour in as-deposited Nb_2O_5 films with accumulation and depletion regions in curves taken from Al/Nb_2O_5/Si(100) capacitors. Post-deposition annealing somewhat reduced the accumulation capacitance, at the same time also reducing the leakage current density.