Characterization of Cu3N films using soft x-ray spectroscopy
Modin, Anders; Kvashnina, Kristina; Butorin, Sergei; Arapan, Sergui; Fallgren, Anna; Ottosson, Mikael; Ahuja, Rajeev; Werme, Lars; Nordgren, Joseph Sweden
Soft X-ray emission and absorption spectroscopy have been used to characterize seven copper nitride films, one synthesized with atomic layer deposition (ALD) and six grown with chemical vapor deposition (CVD) at different preparation temperatures. Characterization of the X-ray spectra was supported by calculations of the electronic structure for bulk pure Cu3N, Cu3N with excess of Cu atoms, oxygen or carbon impurities, and N vacancies. The calculations are shown to be in good agreement with experimental spectra. The interpretation of the X-ray spectra suggests that films grown in copper rich environments and above a cut-off temperature of approximately 360° C has a growing fraction of Cu4N stoichiometry, while films prepared below this temperature only consists of Cu3N stoichiometry.