A semiconductor memory device can include a first conductive line crossing over a field isolation region and crossing over an active region of the device, where the first conductive line can include a first conductive pattern being doped, a second conductive pattern, and a metal-silicon-nitride pattern between the first and second conductive patterns and can be configured to provide a contact at a lower boundary of the metal-silicon-nitride pattern with the first conductive pattern and configured to provide a diffusion barrier at an upper boundary of the metal-silicon-nitride pattern with the second conductive pattern.