Evaluation of MOCVD grown niobium nitride films as gate electrode for advanced CMOS technology

Niobium nitride films were deposited on Si(100) substrates using tert-butylamido-tris-(diethylamido)-niobium (TBTDEN) as the precursor in a commercial state-of-the-art MOCVD reactor. The depositions were carried out in the temperature range 400 - 800oC and the films were characterized for their crystallinity by X-ray diffraction (XRD) and surface morphology by scanning electron microscopy (SEM). Composition studies by secondary neutral mass spectrometry (SNMS) revealed that the films to be stoichiometric niobium nitride with very low concentrations of carbon or oxygen as impurities. Electrical characterization showed that the specific resistivity was strongly dependent on the substrate temperature during deposition. Furthermore, the work function of the as-deposited niobium nitride films and forming gas annealed films were determined.