新型核壳结构相变纳米线的构筑及其多态存储特性研究

本项目拟采用先进的“质量选择团簇束流源技术”制备尺寸高度均一的金纳米团簇，通过控制硅衬底上金团簇催化剂的尺寸与密度分布，并结合对气相法中温度、气压等参数的调控，可控地合成尺寸均一的硫系化合物相变纳米线；深入研究纳米线直径对其相变存储器件存储性能的影响；结合实验与第一性原理计算，研究N/Zn/Ni可控掺杂对Ge2Sb2Te5（GST）纳米线存储单元阈值电压、功耗、晶态/非晶态电阻等性能的影响；在此基础上，构筑核层与壳层成分差别小、晶格失配低的具有稳定多态存储性能的核壳结构纳米线（如N-GST/GST、Zn-GST/GST），研究相变过程中核壳结构纳米线的晶相、成分和界面的具体变化信息，阐明其多态存储机理，揭示核壳纳米线的微观构造（如：核层N/Zn含量、核层直径，壳层厚度）与其宏观多态存储性能和器件可靠性的内在联系，为新型多态存储材料的研发及低功耗、高密度相变存储器的研制提供实验和理论依据。

In this project, mass-selected Au nanoclusters with uniform size will be prepared by a magnetron-sputtering gas-condensation cluster-beam source. Then, by controlling the size and density distribution of Au nanocluster catalysts on Si substrates, and the growth parameters such as temperature and pressure of the gas-phase method, uniform phase-change nanowires (Ge2Sb2Te5 and GeTe) with controlled diameters will be prepared via the gas-phase vapor-liquid-solid mechanism. The effect of the diameter of nanowires on the data storage characteristics of nanowire-based memory will be deeply studied. Moreover, the effect of controllable N/Zn/Ni doping on the storage characteristics of Ge2Sb2Te5 nanowire-based memory including threshold voltage, power consumption, crystalline and amorphous resistance, will be researched based on experimental and theoretical investigations. Furthermore, composition- and lattice-matched N-Ge2Sb2Te5/Ge2Sb2Te5 and Zn-Ge2Sb2Te5/Ge2Sb2Te5 core-shell structured nanowires with stable multi-state switching characteristics will be constructed by pulsed laser deposition using doped Ge2Sb2Te5 nanowires as templates. Structure, composition and interface of the core-shell nanowires will be analyzed during phase transformation. The mechanism of multi-state data storage characteristics, as well as the influences of the nanowire configuration (such as N/Zn content and diameter of the core, shell thickness) on the multi-state data storage characteristics and device reliability will be revealed. The achievements of the project will provide experimental and theoretical basis for development of new materials with multi-state data storage characteristics, and manufacture of the new generation phase-change memory with low power consumption and high density.