Influence of impurity oxygen on the structure and composition of films obtained by sputtering of Nb in Ar-N2 medium

An influence has been studied of the impurity oxygen gas on the structure and the composition of sputtered Nb-N-O films. An increase of the oxygen content in the films takes place at an increase of the partial pressure of N2 reactive gas and a decrease of the ion current onto the target. As a result the films exhibit the transition from the fine-disperse polycrystalline phase δ-NbNO to amorphous Nb2O5 via the two-phase structure (δ-NbNO crystallites in the N2O5 amorphous matrix). It is found that the structure alteration from δNbNO to Nb2O5 is determined by the ratio of Nb-atom fluxes and oxygen onto the substrate and is independent of the presence of N2. The effect of the substrate temperature on the structural state of the phases formed in thin Nb-N-O films is discussed