Scaling Analysis of Nanowire Phase-Change Memory

This letter analyzes the scaling property of nanowire (NW) phase-change memory (PCM) using analytic and numerical methods. The scaling scenarios of the three widely used NW PCM operation schemes (i.e., constant electric field, voltage, and current) are studied and compared. It is shown that if the device size is downscaled by a factor of 1/k (k >; 1), the operation energy (current) will be reduced by more than k³ (k) times, and the operation speed will be increased by k² times. It is also shown that more than 90% of operation energy is wasted as thermal flux into substrate and electrodes. We predict that, if the wasted thermal flux is effectively reduced by heat confinement technologies, the energy consumed per reset operation can be decreased from about 1 pJ to less than 100 fJ. It is shown that reducing NW aspect ratio helps decreasing PCM energy consumption. It is revealed that cross-cell thermal proximity disturbance is counter intuitively alleviated by scaling, leading to a desirable scaling scenario.