The surface damage in titanium nitride associated with lateral sputtering by argon cluster ions

The surface smoothing of TiN coatings, deposited by CVD or PVD methods, by argon ion clusters comprising some 2000 atoms and carrying only a single po sitive charge has been confirmed. In addition, the present work has shown t hat there was no change in the mechanical condition, nanohardness or residu al stress, of the PVD coatings. In contrast, the nanohardness in the near-s urface region of the CVD TiN coating was increased but, remarkably, there w as no concomitant increase in residual stress. A comparison was made with t he established effects of ion implantation on the near-surface properties o f TiN where a high compressive residual stress is developed if the ion ener gy lies beyond a threshold value. It was concluded that the vast majority o f argon atoms from the clusters move sideways on impacting the sample surfa ce, leading to the well-known lateral sputtering effects associated with th e technology, and causing limited surface damage. (C) 2000 Elsevier Science B.V. All rights reserved.