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

Abstract

A multiple phase change structure with Sb79Te21 for switching and Ge1Cu2Te3 for memory was fabricated and evaluated for cell operation. It was confirmed that Sb79Te21 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).