A method is presented for protecting resistive random access memory (RRAM) stacks within a resistive memory crossbar array. The method includes forming conductive lines within an interlayer dielectric (ILD), forming a metal nitride layer over at least one conductive line, forming a bottom electrode, forming a RRAM stack over the metal nitride layer, the RRAM stack including a first top electrode and a second top electrode, undercutting the second top electrode to define recesses, and filling the recesses with inner spacers.