Amorphous-like TiN Films as Barrier Layers for Copper

The titanium nitride (TiN) columnar structure results in a rapid diffusion of copper atoms into the substrate along a vertical path. In this paper, the TiN columnar growth process was modified, which resulted in the deposition of amorphous-like films. The amorphous-like TiN layer demonstrated a low resistivity of 75.3 μΩ·cm. For the test structure of Cu/TiN/SiO2, the Cu diffusion depth in the 3 nm TiN middle layer was only approximately 1 nm after annealing at 750 °C for 30 min. Excellent copper diffusion barrier due to high density and complex diffusion pathways. The results of this study suggest that conventional barrier materials can still be used in ultra-narrow copper interconnects.