A mixture of the tungsten allylimido complexes Cl-4(RCN)W(NC3H5) (1a, R=CH3; 1b, R=Ph) was used to deposit tungsten nitride carbide (WNxCy) films with ammonia as coreactant. Depositions were done in a chemical vapor deposition reactor at temperatures in the range of 450-750 degrees C. The effect of ammonia on film composition, crystallinity, lattice parameter, grain size, film growth rate, and electrical resistivity was studied. Importantly, films grown at 450 degrees C with ammonia as a coreactant were amorphous and showed a roughly five-fold increase in nitrogen content and significantly reduced oxygen levels. The films deposited below 500 degrees C were amorphous, whereas films deposited at and above 500 degrees C were polycrystalline. The X-ray diffraction patterns suggest that either the solid solution beta-WNxCy or beta-WN0.5 and beta-WC0.6 coexist in the films. An Arrhenius plot yielded an apparent activation energy of 0.34 eV for growth from 1a,b and ammonia, compared to the value of 0.15 eV reported for depositions without ammonia. As anticipated, the films deposited with ammonia exhibited higher film resistivity, with the lowest film resistivity of 1.7 m Omega cm observed for films grown at 550 degrees C, compared to 0.29 m Omega cm for film grown without ammonia at 450 degrees C. (C) 2008 The Electrochemical Society.