Advanced interfacial phase change material: Structurally confined and interfacially extended superlattice

• Published in: Materials today (Kidlington, England) Vol. 68; pp. 62 - 73
• Main Authors: Lim, Hyeonwook, Kim, Youngsam, Jo, Kyu-Jin, Seok, Choi, Lee, Chang Woo, Kim, Dasol, Kwon, Gihyeon, Kwon, Hoedon, Hwang, Soobin, Jeong, Kwangsik, Choi, Byung-Joon, Yang, Cheol-Woong, Sim, Eunji, Cho, Mann-Ho
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2023
• Subjects: Doping; Interfacial phase change materials; Neuromorphic; Superlattice; vdW layer; Interfacial phase change materials; vdW layer; Neuromorphic; Superlattice; Doping
• ISSN: 1369-7021; 1873-4103
• DOI: 10.1016/j.mattod.2023.07.025

[Display omitted] Interfacial Phase Change Memory (iPCM) retrench unnecessary power consumption due to wasted heat generated during phase change by reducing unnecessary entropic loss. In this study, an advanced iPCM (GeTe/Ti-Sb2Te3 Superlattice) is synthesized by doping Ti into Sb2Te3. Structural analysis and density functional theory (DFT) calculations confirm that bonding distortion and structurally well-confined layers contribute to improve phase change properties in iPCM. Ti-Sb2Te3 acts as an effective thermal barrier to localize the generated heat inside active region, which leads to reduction of switching energy. Since Ge-Te bonds adjacent to short and strong Ti-Te bonds are more elongated than the bonds near Sb-Te, it is easier for Ge atoms to break the bond with Te due to strengthened Peierls distortions (Rlong/Rshort) during phase change process. Properties of advanced iPCM (cycling endurance, write speed/energy) exceed previous records. Moreover, well-confined multi-level states are obtained with advanced iPCM, showing potential as a neuromorphic memory. Our work paves the way for designing superlattice based PCM by controlling confinement layers.