Epitaxially stabilized TiN/(Ti,Fe,Co)N multilayer thin films in (pseudo-)fcc crystal structure by sequential magnetron sputter deposition

C Klever (1) , K Seemann (1) , M Stüber (1) , S Ulrich (1) , H Brunken (2) , A Ludwig (2) , H Leiste (1)

1 Institute for Materials Research I
2 Institute of Materials

Multilayer thin films were grown by non-reactive sequential magnetron sputter deposition from ceramic TiN and metallic FeCo targets addressing a combination of wear resistance and sensoric functionality. Coatings with bilayer period values ranging from 449 nm down to 2.6 nm were grown with the total amount of either material maintained constant. The multilayer thin films were post-annealed ex-situ at 600 ?C for 60 min in vacuum. X-ray diffraction results imply the multilayer thin films to undergo significant changes in its crystalline structure when the bilayer period is decreased. By using high resolution transmission electron microscopy as well as selected area electron diffraction it is shown that in case of multilayer thin films with bilayer periods of several ten nanometers and higher FeCo layers and TiN layers in their respective common CsCl and NaCl type crystal structures alternate. In contrast, in the multilayer thin films with bilayer periods of only a few nanometers, grain growth across the interfaces between the individual layers takes place and a strongly textured microstructure is formed which features columns in pseudo-fcc crystal structure grown in heteroeptaxial growth mode. It is suggested that the experimental findings imply the latter multilayer thin films to be alternately composed of TiN layers and (Ti, Fe, Co)N solid solution layers which have been formed by solid state reaction during the deposition process. As the consequence, epitaxially stabilised columnar grains in strongly textured pseudo-fcc structure are formed. This structure is preserved after the annealing procedure which qualifies these coatings for use in applications where temperatures of up to 600 ?C are reached.

Mots clés: Physical Sciences

C Klever, K Seemann, M Stüber, S Ulrich, H Brunken, et al.. Epitaxially stabilized TiN/(Ti,Fe,Co)N multilayer thin films in (pseudo-)fcc crystal structure by sequential magnetron sputter deposition. Journal of Physics D: Applied Physics, 2010, 43 (39), pp.395406. ⟨10.1088/0022-3727/43/39/395406⟩. ⟨hal-00629976⟩