One or more diffusion barriers are formed around one or more conductors in a three dimensional or 3D memory cell. The diffusion barriers allow the conductors to comprise very low resistivity materials, such as copper, that may otherwise out diffuse into surrounding areas, particularly at elevated processing temperatures. Utilizing lower resistivity materials allows device dimension to be reduced by mitigating increases in resistance that occur when the size of the conductors is reduced. As such, more cells can be produced over a given area, thus increasing the density and storage capacity of a resulting memory array.