Quasicrystalline phase-change memory

• Published in: Scientific reports Vol. 10; no. 1; p. 13673
• Main Authors: Lee, Eun-Sung, Yoo, Joung E., Yoon, Du S., Kim, Sung D., Kim, Yongjoo, Hwang, Soobin, Kim, Dasol, Jeong, Hyeong-Chai, Kim, Won T., Chang, Hye J., Suh, Hoyoung, Ko, Dae-Hong, Cho, Choonghee, Choi, Yongjoon, Kim, Do H., Cho, Mann-Ho
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13.08.2020; Nature Publishing Group
• Subjects: 639/301/1005/1007; 639/638/263; 639/638/298; 639/638/675; 639/766/119/1002; 639/925/929/115; Crystallography; Energy; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary); Thermal stability
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-70662-2

Phase-change memory utilizing amorphous-to-crystalline phase-change processes for reset-to-set operation as a nonvolatile memory has been recently commercialized as a storage class memory. Unfortunately, designing new phase-change materials (PCMs) with low phase-change energy and sufficient thermal stability is difficult because phase-change energy and thermal stability decrease simultaneously as the amorphous phase destabilizes. This issue arising from the trade-off relationship between stability and energy consumption can be solved by reducing the entropic loss of phase-change energy as apparent in crystalline-to-crystalline phase-change process of a GeTe/Sb 2 Te 3 superlattice structure. A paradigm shift in atomic crystallography has been recently produced using a quasi-crystal, which is a new type of atomic ordering symmetry without any linear translational symmetry. This paper introduces a novel class of PCMs based on a quasicrystalline-to-approximant crystalline phase-change process, whose phase-change energy and thermal stability are simultaneously enhanced compared to those of the GeTe/Sb 2 Te 3 superlattice structure. This report includes a new concept that reduces entropic loss using a quasicrystalline state and takes the first step in the development of new PCMs with significantly low phase-change energy and considerably high thermal stability.