A combined AES, resonant photoemission and EELS study of in-situ grown titanium nitride

Abstract

Samples of titanium nitride were grown in an Ar N atmosphere with various Ar N gas ratios using reactive DC magnetron deposition onto stainless steel and silicon substrates. The samples were transferred to the analysis position in-situ and were studied there using AES, EELS and synchrotron-radiation excited UPS. Using AES, the composition of the samples was found to vary with the Ar N gas ratio, as expected. Changes in the hybridised Ti 3 d N 2p band seen via UPS agreed with the theoretical prediction that the band narrows as the nitrogen concentration is reduced. A large resonance in the Ti 3d band was observed at ∼73 eV, which is probably associated with the Ti 3s level. The UPS and EELS data is consistent with vacancies being present on the titanium sublattice. The EELS data displayed low-energy loss peaks which shifted to higher loss energies as the nitrogen concentration in the film was lowered. These loss peaks can be explained by a screened Drude plasmon loss rather than by intraband transitions. The intensity of the loss peaks was much weaker than previously reported, with attendant implications for explanations of the shape of the Ti 2p photoelectron peak observed in XPS.