Dielectric barrier characteristics of Si-rich silicon nitride films deposited by plasma enhanced atomic layer deposition

This work proposes a new method toward improving dielectric barrier characteristics through low dielectric permittivity (k) amorphous silicon nitride films (SiNx) deposited by plasma enhanced atomic layer deposition (PEALD). The dielectric constants of the atomic layer deposition (ALD) SiNx films were in the range of 4.25–4.71 and were relatively lower than that of SiNx deposited by plasma enhanced chemical vapor deposition (PECVD). The dielectric constants of the PEALD SiNx films were nearly identical to the values for PECVD silicon carbon nitride films (SiCN). Although the ALD SiNx films were low-k, they exhibited similar levels of film stress as PECVD SiNx, and the density of ALD SiNx film was higher than that of PECVD SiCN films. The ability to suppress copper (Cu) diffusion through 10-nm thick SiNx dielectric barriers in silicon dioxide/barrier/Cu/tantalum nitride structures on Si substrates was evaluated via Auger electron spectroscopy analysis. Although PEALD SiNx films possessed low dielectric constants (