Wuhan National Research Center for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
Phys Chem Chem Phys. 2019 Feb 20;21(8):4494-4500. doi: 10.1039/c8cp07446a.
The thermal stability of the amorphous phase is a key property of phase-change memory, which limits the data retention time and device reliability. The high thermal stability of memory devices enables their applications in harsh environments and under extreme conditions. Here, we discovered that the alloying of C, Si and Ge significantly improves the stability of amorphous Sb by adding "alien" tetrahedral seeds to the octahedral matrix. This doping strategy impedes the crystallization at elevated temperatures so that the crystallization temperature of Sb is increased by 170-220 °C. The mechanism is systematically investigated by ab initio molecular dynamics simulations and classical crystal growth theory. We confirm that the alien tetrahedral bonds increase the activation energy of atomic migration upon crystallization. Our results demonstrate an effective alloying strategy to improve the thermal stability of phase change memory, paving the way for the design of durable memory devices.
非晶相的热稳定性是相变存储的一个关键特性，它限制了数据保持时间和器件可靠性。存储器器件的高热稳定性使其能够在恶劣环境和极端条件下应用。在这里，我们发现通过在八面体基体中添加“外来”四面体种子，C、Si 和 Ge 的合金化显著提高了非晶 Sb 的稳定性。这种掺杂策略阻碍了高温下的结晶，从而将 Sb 的结晶温度提高了 170-220°C。通过第一性原理分子动力学模拟和经典晶体生长理论系统地研究了该机制。我们证实，外来四面体键增加了结晶时原子迁移的激活能。我们的结果证明了一种有效的合金化策略，可以提高相变存储的热稳定性，为耐用存储器件的设计铺平了道路。
