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 AND J. FERRÓN

Puerto Iguazú

Simposio; SLAFES XIX - Latin American Symposium on Solid State Physics; 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). A renewed interest has been recently triggered by the possibility of using copper nitrides in the bottom up 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.