The properties of WNxCy films deposited by atomic layer deposition using WF6, NH3, and triethyl boron as source gases were characterized as a diffusion barrier for Cu metallization. It was noted that the as-deposited film exhibited an extremely low resistivity of about 350µΩcm with a film density of 15.37g/cm3. The film composition measured from Rutherford back-scattering spectrometry showed W, C, and N of ~48, 32 and 20at%, respectively. Transmission electron microscopy analyses show that the as-deposited film was composed of face-centered-cubic phase with a lattice parameter similar to both β-WC1–x and β-W2N with an equiaxed microstructure. The barrier property of this atomic layer deposition –WNxCy film at a nominal thickness of 12nm deposited between Cu and Si fails only after annealing (700C, 0.5h).

Atomic-Layer Deposited WNxCy Thin Films as Diffusion Barrier for Copper Metallization. S.H.Kim, S.S.Oh, K.B.Kim, D.H.Kang, W.M.Li, S.Haukka, M.Tuominen: Applied Physics Letters, 2003, 82[25], 4486-8