Thermal disturbance and its impact on reliability of phase-change memory studied by the micro-thermal stage

In this paper, we study thermal disturbance and its impact on reliability using a novel measurement structure - the micro-thermal stage (MTS). The small thermal time constant of the MTS extends the time-scale of temperature dependence measurement to ~100 μs. The reliability of phase-change memory (PCM) is evaluated in terms of data retention and variation of the high resistance (RESET) state resistance (R RESET ) and the threshold switching voltage (V th ). We experimentally show how the impact of thermal disturbances on retention is accumulated and its dependence on the electric field. The thermal disturbance effect on RR RESET variation changes with time and it is the largest for the shortest time delay after RESET programming. Thermal disturbance can cause at least 25 and 100% variation for RR RESET and V th respectively in the given thermal disturbance scenario. We propose an effective method to exploit thermal disturbance to make multi-bit operation more robust.