Atomic-layer-deposited WN[sub x]C[sub y] thin films as diffusion barrier for copper metallization.

The properties of WN[SUBx]C[SUBy] films deposited by atomic layer deposition (ALD) using WF[SUB6], NH[SUB3], and triethyl boron as source gases were characterized as a diffusion barrier for copper metallization. It is noted that the as-deposited film shows an extremely low resistivity of about 350 μΩ cm with a film density of 15.37 g/cm[SUP3]. The film composition measured from Rutherford backscattering spectrometry shows W, C, and N of ∼ 48, 32, and 20 at. %, respectively. Transmission electron microscopy analyses show that the as-deposited film is composed of face-centered-cubic phase with a lattice parameter similar to both β-WC[SUB1-x] and β-W[SUB2]N with an equiaxed microstructure. The barrier property of this ALD-WN[SUBx]C[SUBy] film at a nominal thickness of 12 nm deposited between Cu and Si fails only after annealing at 700 °C for 30 min. [ABSTRACT FROM AUTHOR]