Understanding the Structure and Properties of Phase Change Materials for Data Storage Applications

Abstract

Phase change materials possess a unique property combination which is the basis for their application potential. The amorphous and crystalline phases are characterised by very different optical and electrical properties. This is indicative of a significant structural rearrangement upon the phase transition. Nevertheless, it is possible to rapidly and reversibly switch between the amorphous and crystalline states. This property portfolio has already been successfully employed in rewritable optical data storage. Phase change materials are also considered to be one of the most promising candidates for future electronic memories. Hence, considerable efforts have been undertaken in the past decades to identify suitable materials, and to optimize them with respect to specific applications. This article reviews the structure and the underlying bonding mechanism of phase change materials. This understanding of the bonding mechanism and the resulting atomic arrangement will subsequently be utilized to explain several of the characteristic features of phase change materials. Finally, the technological development both of rewritable optical storage media and future non-volatile electronic memories are reviewed.