Optimization metrics for Phase Change Memory (PCM) cell architectures

We reported here a comparative study of PCM cell architectures. The developed architectures are considered in a program/read efficiency framework and in an integration context. The Self-Heating approach is slightly more efficient, owing to heat generation happening directly within GST, but shows hazardous technology implementation with Ge₂Sb₂Te₅, due to high aspect ratios. The heater-based Wall architecture represents the best and easiest solution for PCM from the technology standpoint: it features relaxed aspect ratios and benefits from lots of geometry-based knobs for optimization with slightly higher process complexity and slightly lower efficiency. Strengths and drawbacks of the different architectures are schematically reported in Fig. 14.