STRUCTURE AND MECHANICAL-PROPERTIES OF DUAL-ION-BEAM DEPOSITED CNXTIYTIN MULTILAYERS/

CNxTiy/TiN multilayers have been synthesized using dual-ion-beam depos ition. X-ray photoelectron spectra of C 1s, Ti 2p, N 1s, and Si 2p ele ctrons were investigated against the depth from the film surface. The results confirm the layered structure of the films. The Ti atoms conta ined in a CNxTiy layer sandwiched between two TiN layers are expected to come from interlayer diffusion of Ti atoms enhanced by ion beam irr adiation during deposition. As a consequence, a CNxTiy layer contains a C-N phase, a Ti-N phase, and a T-C phase. The C-N phase contains 27 at. % nitrogen, less than the level required to form the hypothetical beta-C3N4 phase, indicating that the multilayer structure containing T iN layers does not favor for increasing N content in the C-N phase of the CNxTiy layers. The Ti-N and Ti-C phases are about stoichiometric. The TiN layers comprise mainly a Ti-N phase, and a small fraction of t he Ti-C phase, which are both stoichiometric. However, the bonding bet ween C and N is weak. The hardness H and elastic modulus E of the film s were investigated by nanoindentation experiments. The single-layer C N0.3 is the softest (H=11.4 GPa), and the single-layer TiN is the hard est (H=22 GPa) among the samples in the series. H and E increase with increasing TiN volume fraction, as well as the number of interfaces. T hey also increase with increasing substrate temperature, possibly due to stronger interlayer diffusion of Ti atoms at higher temperature. (C ) 1997 American Vacuum Society.