Materials science and engineering of phase change random access memory

Having monopolised the optical data storage industry since the very beginning, phase change materials are now being intensively explored for next-generation electronic data storage, referred to as phase change random access memory (PCRAM). Because phase change materials are electrically programmable; capable of reversibly switching between two stable structural phases of contrasting electrical properties, besides data storage they also enable data computation. For these reasons, PCRAM envisages to overcome both miniaturisation and data flow bottlenecks, challenges which current silicon charge-based technology is failing to cope with. This review, while reasoning the need for a switch to a newer data storage technology, and comparing PCRAM with other data storage and computation platforms, comprehensively takes stock of the benefits and challenges associated with PCRAM. This review also critically investigates and associates the materials science and physics, such as the atomic structure and bonding, thermodynamics and kinetics of the phase transformation, with the PCRAM device characteristics and performance. Various device design-concepts and requirements are reviewed. Recent advances, and evolution of newer platforms, including those relating to neuromorphic computing and photonic memory are also described. This is the winning review of the 2017 Materials Literature Review Prize of the Institute of Materials, Minerals and Mining, run by the Editorial Board of MST. Sponsorship of the prize by TWI Ltd is gratefully acknowledged