Voltage-Driven On-Off Transition and Tradeoff With Program and Erase Current in Programmable Metallization Cell (PMC) Memory

The transition from the on (low-resistance) to the off (high-resistance) state is studied for programmable metallization cell nonvolatile memories. The stability of the on state under stress voltage and the erase operation were characterized as a function of the initial resistance in the timescale from 100 mus to 100 s. The data suggest that the on-off transition is limited by voltage-driven ion hopping and that filaments with larger size, and hence lower resistance, are more stable. Finally, results are discussed with the aid of an analytical model for erase, which is also used to address the tradeoff between on-state stability and program/erase currents.