NbN film deposition using optical emission spectroscopy

NbN films were deposited on unheated Si substrates by dc and rf reactive planar magnetron sputtering of Nb in an Ar and N2gas mixture. The optical emission spectrum of the plasma was recorded for different sputtering conditions and the target sputtering rate was found to be proportional to the intensity of any Nb emission line. A model for the reactive sputtering mechanism was developed and the optimum sputtering parameters were selected by observing the change in the Nb emission line intensity as a function of the partial pressure of nitrogen. The critical temperatures of the films were in the 13 to 15.8 K range.