Ge-Sb-Te基相变存储材料的相平衡与相转变研究

Ge-Sb-Te合金是目前最为理想的相变存储器材料之一，在探索各类新型相变存储材料的同时，现有成熟材料的各项性能仍需不断提升，以发挥出全新的功能。本项目拟针对掺杂改性的Ge-Sb-Te基相变存储材料，以Ge-Sb-Te-Me(Me=Sc,Se,Ti)多元合金体系为主要研究对象，特别是对于该多元体系所包含的二元和三元基础体系，依据实验测定的相平衡关系和热化学性质，优化和建立热力学数据库。在此基础上，研究掺杂元素在主体相中的溶解度及其随温度和成分的变化；分析高阻值非晶态亚稳相和低阻值多晶态稳定相的生成条件和转化过程；探讨相变材料与限制材料、电极材料、加热材料构成的堆叠膜层间的界面反应生成相的形核驱动力和反应析出序列。利用热力学函数与稳定平衡和亚稳平衡之间、热力学函数与生成相形核驱动力和生成驱动力之间的内在联系，获得理想微观结构的有效形成条件和组织演化规律，促进相变存储材料的快速研究与发展。

In order to accommodate the rapid development of artificial intelligence, big data analytics and supercomputing, the traditional mode for data storage and processing demands a fundamental change. The phase-change random access memory is the next generation of the most attractive nonvolatile memory with high speed and high density, and at present Ge-Sb-Te based alloy is one of the most ideal phase-change materials. While exploring all kinds of new phase-change memory materials, the properties of existing materials still need to be improved continually to play new functions. The present study focuses on doping and improving Ge-Sb-Te based phase-change memory materials, taking the Ge-Sb-Te-Me ( Me = SC, Se, Ti ) multi-component system as the main research object. Especially for the binary and ternary basic systems included in this multi-component alloy system, based on the experimental measurements on phase equilibrium relations and thermochemical properties, a specialized thermodynamic data base is to be optimized and developed. On this basis, it is planned to investigate the solubility of the doping element in the main phase and its variation with operating temperature and alloy composition, to analyze the formation condition and the transformation process of the amorphous metastable phase with high resistance and the polycrystalline stable phase with low resistance, and to explore the nucleation driving forces and the precipitation sequence of the formation phases between the stacking layers of the phase-change material with the confine material, electrode material, heating material, and so on. Taking into account of alloy composition design, process temperature optimization, microstructure morphology control and service performance analysis, and making use of the intrinsic connections between the thermodynamic functions and the stable as well as meta-stable equilibrium relations and between the thermodynamic functions and the nucleation as well as formation driving forces, the effective formation conditions and evolution regularities for ideal microstructures can be obtained, so that to promote profound studies on the interdependencies of composition, microstructure and performance of phase-change memory materials.