Neuromorphic Dynamics at the Nanoscale in Silicon Suboxide RRAM
Neuromorphic Dynamics at the Nanoscale in Silicon Suboxide RRAM
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DOI：
10.3389/fnano.2021.699037
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发表时间：
2021-12
期刊：
影响因子：
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通讯作者：
M. Buckwell;W. H. Ng;D. Mannion;Horatio R. J. Cox;S. Hudziak;A. Mehonic;A. Kenyon
中科院分区：
文献类型：
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作者：
M. Buckwell;W. H. Ng;D. Mannion;Horatio R. J. Cox;S. Hudziak;A. Mehonic;A. Kenyon
电阻式随机存取存储器，也称为忆阻器，其电阻可以通过绝缘体内导电细丝的电驱动形成和破坏来调制，由于其可扩展性，低功率操作和多样化的功能行为，是神经形态应用的有希望的候选者。然而，理解单个细丝和周围材料的动力学是具有挑战性的，这是由于相对于单个细丝的纳米尺度，测试装置的横截面积通常非常大。在目前的工作中，导电原子力显微镜是用来研究在纳米级的导电性的演变在一个完全CMOS兼容的低氧化硅薄膜。报告了独特的非线性塑性和背景电导率增强，表明器件行为可能最好由复合芯（细丝）和壳（背景电导率）动力学描述。此外，恒定电流测量表明细丝形成和断裂之间的相互作用，导致电流控制的电压尖峰在纳米级区域，估计最佳的能量消耗为25阿焦耳每尖峰。这对于极低功耗的神经形态计算是非常有希望的，并且表明在较大设备中观察到的动态行为应该随着尺寸的缩小而持续和改善。
Resistive random-access memories, also known as memristors, whose resistance can be modulated by the electrically driven formation and disruption of conductive filaments within an insulator, are promising candidates for neuromorphic applications due to their scalability, low-power operation and diverse functional behaviors. However, understanding the dynamics of individual filaments, and the surrounding material, is challenging, owing to the typically very large cross-sectional areas of test devices relative to the nanometer scale of individual filaments. In the present work, conductive atomic force microscopy is used to study the evolution of conductivity at the nanoscale in a fully CMOS-compatible silicon suboxide thin film. Distinct filamentary plasticity and background conductivity enhancement are reported, suggesting that device behavior might be best described by composite core (filament) and shell (background conductivity) dynamics. Furthermore, constant current measurements demonstrate an interplay between filament formation and rupture, resulting in current-controlled voltage spiking in nanoscale regions, with an estimated optimal energy consumption of 25 attojoules per spike. This is very promising for extremely low-power neuromorphic computation and suggests that the dynamic behavior observed in larger devices should persist and improve as dimensions are scaled down.