R. Lahoz, J.P. Espinós, F. Yubero, A.R. González-Elipe, G.F. de la Fuente
Journal of Material Research, 30 (2015) 2967-2976
doi: 10.1557/jmr.2015.190

This work studies the nitridation of Ta by laser irradiation by means of x-ray photoelectron spectroscopy. The study has been carried out under “in situ” conditions by controlling the nitrogen partial pressure, the presence of traces of oxygen, and the irradiance of the laser. It is found that a thin layer of Ta₂O₅ is directly obtained when irradiating in the presence of oxygen, while a Ta₃N₅ surface compound and some minor contributions of nonstoichiometric phases are formed in the presence of nitrogen. For O₂:N₂ mixtures at 0.1 Pa, preferential nitride formation occurs up to a ratio of 1:4, while Ta₂O₅ starts to be predominant for ratios above this value. The air stability of the tantalum nitride layer formed by laser irradiation and the surface topography of the irradiated metal are also studied. The possible factors determining this behavior are discussed.