R&D: Recipe for Ultrafast and Persistent Phase-Change Memory Materials

NPG Asia Materials has published an article written by Keyuan Ding, College of Materials Science and Engineering, Shenzhen University, 518060, Shenzhen, China, Bin Chen, College of Materials Science and Engineering, Shenzhen University, 518060, Shenzhen, China, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, 518060, Shenzhen, China, Yimin Chen, Department of Microelectronic Science and Engineering, School of Physical Science and Technology, Ningbo University, 315211, Ningbo, China, and Laboratory of Infrared Material and Devices & Key Laboratory of Photoelectric Materials and Devices of Zhejiang Province, Advanced Technology Research Institute, Ningbo University, 315211, Ningbo, China, Junqiang Wang, CAS Key Laboratory of Magnetic Materials and Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, 315201, Ningbo, China, Xiang Shen, Laboratory of Infrared Material and Devices & Key Laboratory of Photoelectric Materials and Devices of Zhejiang Province, Advanced Technology Research Institute, Ningbo University, 315211, Ningbo, China, and Feng Rao, College of Materials Science and Engineering, Shenzhen University, 518060, Shenzhen, China.

Abstract: “The contradictory nature of increasing the crystallization speed while extending the amorphous stability for phase-change materials (PCMs) has long been the bottleneck in pursuing ultrafast yet persistent phase-change random-access memory. Scandium antimony telluride alloy (Sc_xSb₂Te₃) represents a feasible route to resolve this issue, as it allows a subnanosecond SET speed but years of reliable retention of the RESET state. To achieve the best device performances, the optimal composition and its underlying working mechanism need to be unraveled. Here, by tuning the doping dose of Sc, we demonstrate that Sc_0.3Sb₂Te₃ has the fastest crystallization speed and fairly improved data nonvolatility. The simultaneous improvement in such ‘conflicting’ features stems from reconciling two dynamics factors. First, promoting heterogeneous nucleation at elevated temperatures requires a higher Sc dose to stabilize more precursors, which also helps suppress atomic diffusion near ambient temperatures to ensure a rather stable amorphous phase. Second, however, enlarging the kinetic contrast through a fragile-to-strong crossover in the supercooled liquid regime should require a moderate Sc content; otherwise, the atomic mobility for crystal growth at elevated temperatures will be considerably suppressed. Our work thus reveals the recipe by tailoring the crystallization kinetics to design superior PCMs for the development of high-performance phase-change working memory technology.“