Tungsten nitride thin films deposited by MOCVD: sources of carbon and effects on film structure and stoichiometry

MOCVD was used to deposit tungsten nitride thin films from solutions of Cl 4(CH 3CN)W(N iPr) in 1,2-dichlorobenzene (1,2-DCB). Results were compared to previous depositions from benzonitrile (PhCN) solutions in order to determine whether the solvent affected deposition of carbon into the films. The rate of carbon deposition was solvent-dependent, with apparent activation energies in films from PhCN and 1,2-DCB solutions being 0.70±0.10 eV and 1.0±0.14 eV, respectively. Residual gas analysis results were consistent with solvent decomposition in the reactor, and increased nitrogen levels for films from PhCN solutions suggest that the nitrile (CN) group was a significant carbon source.