A Review of Advances in Deposition Methods and Material Properties of Superlattice Phase-Change Memory

Phase-change memory (PCM) has emerged as a promising candidate for next-generation nonvolatile memory due to its rapid read and write speeds, long data retention, and high scalability. However, its relatively high-power consumption has hindered widespread adoption across various applications. A phase-change material, Sb2Te3/GeTe superlattice (ST/GT SL), holds the potential to address this issue due to its lower programming power compared to conventional PCM devices. The crystal orientation formed during the deposition step significantly influences the performance of the SL, thereby necessitating the development of various deposition methods with precise control over each layer. First, this article introduces the fundamental motivations for studying the ST/GT SL. Then, different deposition techniques for SL films are explained, elucidating their merits/demerits and impact on the PCM device performances. Subsequent sections discuss the atomic configuration of the ST/GT SL, comparing proposed models with experimental results. Also, the switching mechanisms behind low-power switching are discussed with the insights gained from the atomic configuration. The final section briefly summarizes the essential findings and performance evaluations and provides an outlook for the material design for high-density and high-performance applications.