Synthesis of carbon nitride thin films by low-energy ion beam assisted evaporation: on the mechanisms for fullerene-like microstructure formation


Synthesis of carbon nitride thin films by low-energy ion beam assisted evaporation: on the mechanisms for fullerene-like microstructure formation

Gago, R.; Neidhardt, J.; Vinnichenko, M.; Kreissig, U.; Czigány, Z.; Hultman, L.; Kolitsch, A.; Moeller, W.

Carbon nitride (CNx) thin films were grown at different substrate temperatures by low-energy (<100 eV) ion beam assistance deposition (LE-IBAD) in order to discern possible formation mechanisms of a fullerene-like (FL) microstructure. The samples were characterized by elastic recoil detection analysis, Raman spectroscopy, spectroscopic ellipsometry, and high-resolution transmission electron microscopy. The results are compared to those of well-structured FL-CNx films synthesized by reactive magnetron sputtering (MS). The comparison yields similar trends for both techniques, such as limitation of the nitrogen content at 20-25 at. %, dominance of sp2 hybrids, as well as thermally activated chemical desorption of CxNy species from the substrate during growth. However, CNx films produced by LE-IBAD are amorphous and, thus, lack FL features. This result correlates with a lower sp2 clustering, attributed to the promotion of nitrile groups. Therefore, low-energy ion bombardment is shown not to be a sufficient condition for the FL microstructure formation. An important difference in the film-forming fluxes between both techniques is the contribution of pre-formed CxNy species from the sputtering target in MS. These species may play a determinant role, serving as precursors for the introduction of FL arrangements during growth.

  • Thin Solid Films 483(2005)1-29, 89-94

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Publ.-Id: 6124