Surface characterization of nitride structures on Cu(001) formed by N ions implantation: an AES, XPS and LEIS study

L.J. CRISTINA; R.A. VIDAL; J. FERRÓN.

Congreso; 93da Reunión Nacional de Física y XI de la Sociedad Uruguaya de Física; 2008

Copper nitrides have received a certain amount of attention in the past mostly related to its possible applications in the developing of write-once optical recording media (WORM) and in the design of nanostructure devices. In fact, the low energy ion bombardment of Cu (001) with N2+ followed by a mild annealing generates self-assembled nanostructures.  In this work, we study the formation of copper nitrides under N2+ bombardment by means of Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and low ion energy spectroscopy (LEIS).      We characterize the N diffusion features as a function of the substrate temperature by AES, the chemical state of N and Cu by XPS and the atomic structure of the surface by LEIS. We find that the N binding energy shifts non-monotonously along the whole process pointing out that the charge transfer between N and Cu depends not only of the N amount but also of the atomic rearrangement. We also find that N locates on the fourfold hollow site of the Cu(001) surface. Our LEIS results are compatible with a c(2x2) ordering, but at the same time we cannot disregard that some N atoms are either located in c(1x1) sites or substituting Cu atoms.