Chalcogenide Phase Change Memory: Scalable NVM for the Next Decade?

Non-Volatile Memories (NVM) are playing an important role in the semiconductor market, thanks in particular to Flash which is used mainl y in cellular phones and other types of electronic portable equipment. In the coming years portable systems will demand even more NVM with high density and very high writing throughput for data storage application, or with fast random access for code execution. While continued research on floating gate techniques should extend the current Flash technology capability through the end of this decade, there is increasing interest in new memory storage mechanisms and materials that have promise for scaling thr ough at least the end ofthe next decade. Among the different NVM based on storage mechanisms alternative to the floating-gate concept, Phase-Change Memories (PCM), also called Ovonic Unified Memory (OUM), is one of the most promising candidates, having the potentia l to improve the performance compared to Flash as well as to be scalable beyond Flash technology [1-3]. In this paper the physics and operation of phase change memory will first be presented, followed by a discussion on the current status of development. Finally, the scaling capability of the technology will be presented.