Reliability issues and scaling projections for phase change non volatile memories

While the semiconductor industry is gaining confidence in the phase change memory (PCM) technology, many issues about reliability and scaling limitations are still debated. PCM reliability is mainly affected by crystallization and relaxation mechanisms in the metastable amorphous structure. The ultimate scaling limit for PCM is also believed to be determined by the structural stability of nm-sized amorphous volumes. To improve the reliability and to predict the ultimate scaling perspectives of PCM technology, a comprehensive understanding of crystallization and relaxation physics is necessary. This work reviews the current understanding of the reliability properties of PCMs. The possibility to tailor the cell reliability by composition changes in the chalcogenide material will be addressed. Experimental results about size-dependent crystallization in amorphous chalcogenide materials will be finally discussed.