Adsorption and Surface Diffusion of Atomic Ru on TiN and SiO₂: A First-Principles Study

Ruthenium (Ru) has been suggested as one of the promising materials for nanoscale interconnects to substitute copper (Cu) that is currently used in the semiconductor industry. Through density functional theory (DFT) calculations, we present the rationales for varying deposition behavior of Ru on different types of substrates. For the SiO2 and TiN substrates, with and without adsorbed hydrogen, our calculation results reveal the adsorption sites and their adsorption energy, the surface diffusion paths and their activation energy, and the surface diffusion coefficients. We confirm that the adsorption of Ru is more stable on TiN than on SiO2 substrates, and that the surface diffusion of Ru adatom is faster on TiN than on SiO2 surface.