The origin of hexagonal phase and its evolution process in Ge2Sb2Te5 alloy
APL Materials(2022)
摘要
Ge2Sb2Te5 (GST) is the most important material for phase change random access memory (PCRAM) applications, while the formation of hexagonal (h-) phase results in low switching speed, large energy consumption, and worse endurance performance. Uncovering the formation mechanism of h-phase is beneficial for the further improvement of GST-based PCRAM devices. In this work, through advanced spherical aberration corrected transmission electron microscopy and transmission electron back-scattered diffraction technique, the mechanism of h-phase microstructure evolution is clearly clarified. We find that the vacancy ordering is more likely to appear around the grain boundary in a face-centered-cubic (f-) phase grain, which is the starting point for the generation of h-phase. More specifically, all the atoms in f-phase undergo a gradual shift into h-lattice positions to complete the f-to-h structural transition. By introducing an elemental dopant, for instance, carbon (C), the aggregation of C clusters prefers to distribute in the grain boundary area, which is the essential reason for postponing the generation and expansion of h-phase and greatly improving the thermal stability of C-GST material. In short, clarification of the origin of h-structure incubated from f-phase guides the optimization strategy of GST-based PCRAM devices.& nbsp;(c) 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(http://creativecommons.org/licenses/by/4.0/).
更多查看译文
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要