Multiple phase change structure for the scalable phase change random access memory array

A multiple phase change structure with Sb₇₉Te₂₁ for switching and Ge₁Cu₂Te₃ for memory was fabricated and evaluated for cell operation. It was confirmed that Sb ₇₉Te₂₁ with smaller contact diameter is successfully operated or used as a switching device with selective current pulses. In addition, it was estimated that this structure provides acceptable on-off ratio and leakage current by structural consideration. From these results, we consider that the structure with multiple phase change materials is suitable as a new device with both switching and memory functions, which gives higher scalability in three-dimensional array architecture by adopting no additional selective devices, such as transistors and diodes. Therefore, we expect that this structure can be one of the candidates for the scalable phase change random access memory (PCRAM).