焦耳热与原子开关导电细丝随机性分布的相关性及焦耳热的原位缺陷态构造研究

The random growth of conductive filament in Atomic switch is one of the biggest obstacles that restrict its application. It is one of the key factors that affect the inherent mechanism of the formation of conductive filaments and the formation of Atomic switches for specific conductive filament channels. It is generally believed that the amorphous structure of the electrolyte affects the randomness of the conduction position of the conductive filaments. However, combined with the theory of thermal conductivity, Cu-based Ta2O5 atomic switch, due to the influence of Joule heating, the temperature around conductive filament tip will be as high as 1400 ℃, which will change the defect state and leakage current density in the region, which will affect the re-formation of conductive filaments position. In the experiment, the influence of different Joule heating on the locations of conductive filament was studied. The Ta2O5 film thermal annealing was used to simulate the effects of Joule heating in situ and the interaction between Joule heating and the conduction position of conductive filament was verified. And then clarify the relationship between Joule heating and random growth mechanism of conductive filament. Based on this, based on the microstructure of the solid electrolyte, the in-situ annealing of Joule heating was used to generate the defect state or the hole, thus Atomic switch with the position of the conductive filament and good data retention was prepared. To develop Atomic switch compatible with low-voltage CMOS technology provides theoretical basis and experimental data support.

原子开关阻变存储器中导电细丝的随机生长是制约其应用的最大障碍之一，阐明影响导电细丝形成的内在机制、形成有特定连通导电细丝通道的原子开关，成为其应用的关键因素之一。一般认为，电解质的非晶结构是影响形成导电细丝导通位置随机性的原因。然而，我们根据热导理论计算，以Cu基Ta2O5原子开关为例，由于焦耳热的影响，导电细丝尖端温度将超过1400℃，这将改变该区域缺陷态及漏电流密度，进而影响再次形成导电细丝的位置。本项目将通过对不同焦耳热影响下导电细丝位置统计，以Ta2O5薄膜快速退火模拟焦耳热原位退火影响，验证所提出的焦耳热与导电细丝导通位置随机性之间的作用关系模型，进而阐明焦耳热对导电细丝随机生长的影响机制。在此基础，从电解质微结构出发，设计利用焦耳热原位退火生成缺陷态或孔洞，从而制备导电细丝位置确定、数据保持性好的原子开关，为开发与低压CMOS工艺兼容的原子开关阻变存储器提供理论依据和实验支撑。

原子开关阻变存储器中导电细丝的随机生长是制约其应用的最大障碍之一，阐明影响导电细丝形成的内在机制、形成有特定连通导电细丝通道的原子开关，成为其应用的关键因素之一。本项目将通过对不同焦耳热影响下导电细丝位置统计，阐明焦耳热与导电通道形成随机性之间的作用机制，进而提出方案优化原子开关器件运行参数。本项目主要开展了三个方面的研究工作：（1）焦耳热与原子开关导电通道形成随机性之间的作用机制。为了更好的统计焦耳热影响对导电细丝形成数量的影响，采用平面原子开关器件方案，通过选用高离子电导率的固体电解质材料，观测到了导电细丝的形成和位置，并在器件开关运行中，清晰观察到导电细丝的位置、形态和形成机制的变化；（2）基于焦耳热方程，计算有机碳结构体系和无极非晶氧化碳原子开关中焦耳热温度，并通过优化不同热学参数有机碳结构堆叠方式、导电细丝形态变化、耐温性好固态电解质，避免焦耳热的影响，制作运行稳定性和一致性大幅提交的原子开关器件；（3）优化溅射沉积氧化碳阻变层制备工艺，利用导电细丝的形成过程热的积累导致导电细丝局部区域温度上升，C-O键容易断裂实现局部结构重整，在焦耳热的影响下在细丝局域构造出缺陷浓度集中、密度较低、有利于离子迁移的新的导电通道用，从而获得了一致性大为改善的原子开关器件。项目所取得的成果对于设计制作运行参数稳定的原子开关器件具有重大的理论意义和实际应用价值。