Abstract
Nitride thin films in the Cu3N-TiN system were prepared by a reactive sputtering method. Analyses of X-ray photoelectron spectra and X-ray absorption spectra for the films revealed the following.
(1) The valence state of copper is nearly equal to unity in both Cu3N and the anti-rhenium trioxide-type solid solutions in the Cu3N-TiN system, and the charge transfer occurs from copper to nitrogen.
(2) Copper has a peculiar electronic state in Cu3N compared to metal atoms in other metal nitrides, i.e., 3d electrons of copper are quite localized.
(3) With the addition of TiN, the contribution of 3d electrons of metal to the levels consisting of metal 3d electrons and nitrogen 2p electrons increases, and the bonding state seems to become band-like one. These electronic states are considered to play an important role on the thermal stability of anti-rhenium trioxide-type Cu3N and nitride films in the Cu3N-TiN system.
