MoS₂ Synthesized by Atomic Layer Deposition as Cu Diffusion Barrier

Miniaturization in integrated circuits requires that the Cu diffusion barriers located in interconnects between the Cu metal line and the dielectric material should scale down. Replacing the conventional TaN with a 2D transition metal dichalcogenide barrier potentially offers the opportunity to scale to 1–2 nm thick barriers. In this article, it is demonstrated that MoS 2 synthesized by atomic layer deposition (ALD) can be employed as a Cu diffusion barrier. ALD offers a controlled growth process at back‐end‐of‐line (BEOL) compatible temperatures. MoS 2 films of different thicknesses (i.e., 2.2, 4.3, and 6.5 nm) are tested by time‐dependent dielectric breakdown (TDDB) measurements, demonstrating that ALD‐grown MoS 2 can enhance dielectric lifetime by a factor up to 17 at an electric field of 7 MV cm −1 . Extrapolation to lower E‐fields shows that the MoS 2 barriers prepared by ALD have at least an order of magnitude higher median‐time‐to‐failure during device operation at 0.5 MV cm −1 compared with MoS 2 barriers prepared by other methods. By scaling the thickness further down in future work, the ALD MoS 2 films can be applied as ultrathin Cu diffusion barriers.