SFB 917: Resistively Switching Chalcogenides for Future Electronics - Structure, Kinetics and Device Scalability: 'Nanoswitches'

对数据存储和处理的需求继续呈指数级增长。为了应对日益增加的数据存储和处理负担，迫切需要在计算体系结构和硬件方面进行改变。SFB 917的目标是使用纳米开关来实现新的存储设备和新的计算范例。在SFB 917的第二个报告期内，取得了重大进展。特别是，我们对VCM器件的纳米级氧化还原过程有了深入的了解，并可以描述超过14个数量级的开关动力学。这些洞察力帮助我们在不到350 ps的时间内切换VCM材料，而根据DFT计算，可以在不到1 ns的时间内切换功率更低的卓越PC材料。最后但并非最不重要的是，我们在晶态相变材料中发现了一种新的成键机制，它与教科书中讨论的三种主要成键机制(离子、金属和共价)有显著不同。这些洞察力导致了一张包含所有四种主要成键机制的新奇地图。这意味着可以使用该映射来定制具有所需特性的阻性开关。因此，在第三个资助期，我们可以采用合理的材料设计来推进对电阻开关现象的微观理解。我们打算利用这种藏宝图来探索VCM和PCM的应用潜力的极限。特别相关的是切换速度、可扩展性和可靠性方面的限制，因为这些限制将定义这种材料类别可以预见的应用范围。因此，我们计划采用几种不同的概念来生产纳米尺寸的开关，并利用我们在前两个资助期开发的分析和表征方法平台来研究它们的开关速度和可靠性。我们将研究新的、有希望的VCM变体的物理学，并研究限制相应细胞可靠性的微观机制。对于VCM和PCM，我们计划基于已经详细说明的宝藏图来探索可伸缩性的限制。

The demand for data storage and processing continues to increase exponentially. To cope with the in-creased burden on data storage and processing, changes in computing architecture and hardware are urgently needed. It is the goal of SFB 917 to employ nanoswitches to realize novel storage devices and new computing paradigms. In the second reporting period of SFB 917 significant advances have been made. In particular, we gained an in-depth understanding of the nanoscale redox-processes of VCM devices and could describe the switching kinetics over 14 orders of magnitude. These insights have helped us to switch VCM materials in less than 350 ps, while a superior PC material could be identified based on DFT calculations which switches with reduced power in less than 1 ns. Last but not least, we have identified a novel bonding mechanism in crystalline phase change materials, which differs significantly from the three main bonding mechanisms (ionic, metallic and covalent) discussed in textbooks. These insights have led to a novel map containing all four major bonding mechanisms. This implies that resistive switches with desirable properties can be tailored with this map. Hence, in the third funding period we can employ rational materials design to advance the microscopic understanding of resistive switching phenomena. We intend to employ such treasure maps to explore the limits of the application potential of VCMs and PCMs. Of particular relevance are the limits in switching speed, scalability and reliability, since these will define the range of applications that can be envisioned for this material class. We hence plan to employ several different concepts to produce nanosize switches and study their switching speed and reliability with the platform of analysis and characterization methods we have developed in the first two funding periods. We will study the physics of new, promising VCM variants and investigate the microscopic mechanisms which limit the reliability of corresponding cells. For both, VCM and PCM, we plan to explore the scalability limits based on the treasure maps which have been elaborated.