In operando investigation of resistive switching in electron transparent lamellae of HfOx based RRAM devices

基于 HfOx 的 RRAM 器件的电子透明薄片中电阻开关的操作研究

• 批准号: 384682067
• 负责人: Professor Dr. Lambert Alff
• 金额: --
• 依托单位: Fachgebiet Dünne Schichten
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/384682067?language=en
• 关键词: operando; investigation; resistive; switching; electron

Resistive random access memory (RRAM) switches, also called memristors, are promising candidates for fast non-volatile memory. Among the transition metal oxides serving as the functional material, HfOx and TaOx have attracted high interest due to their performance and proven compatibility with complementary metal-oxide-semiconductor (CMOS) technology. Despite the huge amount of work done in this research area, an atomistic understanding of the switching process is still much debated. It is a so far an unrealized dream of many scientists in the field, to directly study with atomic resolution the structural and electronic changes in the functional materials occurring in the different stages of the switching operation (formation, set and reset). Based on our very recently established process to in situ electrically contact and operate an electron transparent focused ion beam (FIB) prepared lamella cut from a RRAM structure, we are now in the position to propose a previously not possible set of experiments. This include the visualization of the local oxygen stoichiometry in the vicinity of the filament by scanning transmission electron microscopy in combination with electron energy-loss spectroscopy (STEM-EELS), the study of the size scaling behavior of lamellae and their switching behavior in controlled oxygen atmospheres with contacted and operating free-standing lamellae and as most risky part and ultimate goal, the direct visualization of the conducting filament with atomic resolution under electric bias in operando. If successful, it would be the first time that a conductive filament is visualized by direct imaging techniques. Based on the obtained results, we intent to develop a model for resistive switching that correlates the macroscopic device behavior with the atomic scale resolved nanostructure of the conducting filament.

电阻式随机存取存储器（RRAM）开关，也称为忆阻器，是快速非易失性存储器的有希望的候选者。在作为功能材料的过渡金属氧化物中，HfOx和TaOx由于其性能和与互补金属氧化物半导体（CMOS）技术的兼容性而引起了人们的高度关注。尽管在这一研究领域做了大量的工作，但对转换过程的原子理解仍然存在很多争议。用原子分辨率直接研究功能材料在开关操作（形成、设置和复位）的不同阶段所发生的结构和电子变化，是目前许多科学家尚未实现的梦想。基于我们最近建立的原位电接触和操作从RRAM结构切割的电子透明聚焦离子束（FIB）制备的薄片的工艺，我们现在可以提出一组以前不可能的实验。这包括通过扫描透射电子显微镜结合电子能量损失光谱（STEM-EELS）可视化灯丝附近的局部氧化学计量，研究片层的尺寸缩放行为及其在受控氧气气氛中与接触和操作的独立片层的切换行为，并作为最危险的部分和最终目标。电偏压下导电灯丝原子分辨率的直接可视化。如果成功，这将是第一次通过直接成像技术可视化导电丝。基于所获得的结果，我们打算建立一个将宏观器件行为与导电灯丝的原子尺度分解纳米结构相关联的电阻开关模型。