The spatially resolved optical emission spectroscopy of various species of a pulse DC unbalanced magnetron sputtering is studied. Ar-N-2 gas mixtures are used. Emission lines corresponding to titanium cathode and gas discharge species are considered. In this study, the two-dimensional (2-D) emission profiles of the lines are measured by an ICCD camera during TiN coatings. It turns out that the 2-D emission profiles of the various lines behave differently. As a result, we obtained the surface roughness value of RMS 2.3 nm at higher pulse frequency and 3.8 nm at lower pulse duty cycle. (C) 2004 Elsevier B.V. All rights reserved.