Sb Rich Ge₂Sb₅Te₅ Alloy for High-Speed Phase Change Random Access Memory Applications

Sb rich Ge₂Sb₅Te₅ materials are investigated for use as the storage medium for high-speed phase change memory (PCM). Compared with conventional Ge₂Sb₂Te₅, Ge₂Sb₅Te₅ films have a higher crystallisation temperature (～200°C), larger crystallisation activation energy (3.13 eV), and a better data retention ability (100.2°C for ten years). A reversible switching between set and reset states can be realised by an electric pulse as short as 5 ns for Ge₂Sb₅Te₅-based PCM cells, over 10 times faster than the Ge₂Sb₂Te₅-based one. In addition, Ge₂Sb₂Te₅ shows a good endurance up to 3×10⁶ cycles with a resistance ratio of about three orders of magnitude. This work clearly reveals the highly promising potential of Ge₂Sb₅Te₅ films for applications in high-speed PCM.