Tungsten carbide films were grown by chemical vapor deposition using W(CO)(6) and C2H4 between 250 and 450 degreesC. Pyrolysis studies indicate W(CO), thermally decomposes over the 150-200 degreesC temperature range with or without ethylene. Carbon incorporation increased from 13 to similar to 33% when C2H4 was co-fed with W(CO)(6). The W/C carbon ratio, as established by X-ray photoelectron spectroscopy (XPS), remained approximately 2:1 regardless of the C2H4 to W(CO)(6) flow ratio for temperatures between 250 degrees and 450 degreesC. Films (50 nm thick) grown at 290 degreesC have a resistivity of 250 mu Omega -cm. Above 500 degreesC, the W/C ratio decreased to similar to1:1.25 and the resistivity increased to 535 mu Omega -cm. The tungsten and carbon are present in the tungsten carbide chemical state. X-Ray diffraction, XPS, selected area electron diffraction and transmission electron microscopy analysis reveal the films are a mixture of 5-6 nm W2C crystallites in an amorphous matrix, whose stoichiometry is similar to2:1 W/C. Copper was not found to diffuse through 7-nm-thick tungsten carbide films in Cu/WC/SiO2 stacks that were annealed at 400 degreesC for 8-9 h.