Sputtered Ru–Ti, Ru–N and Ru–Ti–N films as Cu diffusion barrier

Ultrathin Ru–Ti alloy, Ru–N and Ru–Ti–N films were fabricated as diffusion barriers to Cu metallization. The thermal stability, phase formation, surface morphology and atomic depth profile of the Cu/Ru–Ti(10 nm)/Si, Cu/Ru–N(10 nm)/Si and Cu/Ru–Ti–N(10 nm)/Si structures after annealing at different temperatures were investigated. Comparing to the single Ru layer, both N doping and Ti alloying improve the thermal stability and diffusion barrier properties to Cu. The Cu on the Ru–Ti layer has better morphology than Cu on the Ru–N layer, while the Ru–Ti–N layer has the best thermal stability and has great potential to be applied as a single layer diffusion barrier.