Study of diffusion barrier properties of ternary alloy (TixAlyNz) in Cu/TixAlyNz/SiO2/Si thin film structure

Abstract

The effects of aluminum (Al) incorporation on the performance of a titanium nitride (TiN) diffusion barrier were investigated up to the temperature of 1000 °C in the Cu/TixAlyNz/SiO2/Si structure. The thermal stability of the structure was evaluated by using four-point probe, X-ray diffraction, and Rutherford Backscattering Spectroscopy. The Cu/TixAlyNz/SiO2/Si system retained its structure up to 1000 °C. The incorporation of Al into the TixNy film modified the microstructure of the TixNy film, especially the microstructure of grain boundaries in which oxide and nitride compounds of Al and Ti were formed during thermal annealing. As a result, the fast pathways for copper (Cu) diffusion were effectively blocked by these compounds and the stability of the barrier performance was enhanced up to 1000 °C.