Pulsed power magnetron sputtering of a niobium target in reactive oxygen and/or nitrogen atmosphere

The behavior of a mobium target during magnetron sputtering in reactive oxygen and/or nitrogen atmosphere using a pulsed power supply has been investigated. No arcing was observed at any deposition conditions. Deposition rates in the system Nb-O-N were in the range of 0.8-3.6 mu m/h. The highest rates were found for low oxygen flows in the Nb-O system. The chemical composition, morphology and crystallographic structure of deposited Nb-O and Nb-O-N coatings have been studied by energy dispersive X-ray spectroscopy, scanning electron microscopy and X-ray diffraction, respectively. Hardness measurements were performed using the instrumented indentation test. As for other Me-O-N systems (Me=metal) the oxygen has a strong influence on the chemical composition of the Nb oxynitride coatings due to its higher reactivity compared with nitrogen. Nb-O coatings deposited at oxygen gas flows >5 sccm look transparent, at lower oxygen gas flows the coatings appear metallic. Oxygen gas flows >5 scent do not influence the chemical composition or hardness of the coatings appreciably (saturation effect). Additions of nitrogen shift the transition "metallic-transparent" to lower oxygen gas flows. Nb-O and Nb-O-N coatings seem to be X-ray amorphous. The hardness of the transparent Nb-O-N coatings is lower than the hardness of a metallic niobium coating. (c) 2005 Elsevier B.V All rights reserved.