The growth and diffusion barrier properties of atomic layer deposited NbNx thin films

NbNx thin films were grown by the atomic layer deposition method using niobium chloride and ammonia as precursors. The deposition temperature was varied between 250 and 500 °C. The film properties were analyzed by energy dispersive X-ray spectroscopy, time-of-flight elastic recoil detection analysis, X-ray diffraction, and the standard four-point probe method. Additionally the diffusion barrier properties of approximately 10 nm thick NbNx thin films deposited at 350, 400, and 500 °C were studied. As a comparison the barrier properties of Nb(Ta)N and Nb(Ti)N thin films deposited at 400 °C were studied. The breakdown temperatures of the annealed Cu/barrier/Si structures were determined from the X-ray diffraction data, sheet resistance values, and etch-pit results.