Structure refinement and hardness enhancement of titanium nitride films by addition of copper

Titanium nitride films with a low added copper content were synthesized by ion beam-assisted sputtering deposition. The role of copper was examined with regard to the structure, hardness and elastic/plastic deformation capacity of the composite Rims produced. It was found that copper had significant modifying effects on the structure and property of titanium nitride films. When a very low content of Cu (< 2 at.%) was added, the film showed apparent hardness enhancement. Films with low content of Cu also displayed highly elastic characteristics (91% elastic recovery under nanoindentation). On the contrary, films with > 2 at. % copper were comparatively soft, up to 53% of the deformation under indentation could be plastic in this case. In addition, copper additions could also be used to tune the grain size of TiN in the range of 25-5 nm, at the same time causing a transition from a strong (111) preferred orientation to random polycrystalline morphology. (C) 2001 Elsevier Science B.V. All rights reserved.