Kang Jaehyeon, Won Jongun, Han Narae, Hong Sangjun, Yang Jee-Eun, Kim Sangwook, Kim Sangbum
Department of Material Science & Engineering, Inter-university Semiconductor Research Center (ISRC), Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul, 08826, Republic of Korea.
Device Solutions, Samsung Electronics, Hwaseong, 18479, Republic of Korea.
Adv Sci (Weinh). 2025 Jun;12(23):e2417635. doi: 10.1002/advs.202417635. Epub 2025 May 20.
On-chip training in analog in-memory computing (AIMC) holds great promise for reducing data latency and enabling user-specific learning. However, analog synaptic devices face significant challenges, particularly during parallel weight updates in crossbar arrays, where non-uniform programming and disturbances often arise. Despite their importance, the disturbances that occur during training are difficult to quantify based on a clear mechanism, and as a result, their impact on training performance remains underexplored. This work precisely identifies and quantifies the disturbance effects in 6T1C synaptic devices based on oxide semiconductors and capacitors, whose endurance and variation have been validated but encounter worsening disturbance effects with device scaling. By clarifying the disturbance mechanism, three simple operational schemes are proposed to mitigate these effects, with their efficacy validated through device array measurements. Furthermore, to evaluate learning feasibility in large-scale arrays, real-time disturbance-aware training simulations are conducted by mapping synaptic arrays to convolutional neural networks for the CIFAR-10 dataset. A software-equivalent accuracy is achieved even under intensified disturbances, using a cell capacitor size of 50fF, comparable to dynamic random-access memory. Combined with the inherent advantages of endurance and variation, this approach offers a practical solution for hardware-based deep learning based on the 6T1C synaptic array.
模拟内存计算(AIMC)中的片上训练在减少数据延迟和实现用户特定学习方面具有巨大潜力。然而,模拟突触器件面临重大挑战,特别是在交叉阵列中的并行权重更新期间,经常会出现非均匀编程和干扰。尽管干扰很重要,但基于清晰的机制难以量化训练期间发生的干扰,因此,它们对训练性能的影响仍未得到充分探索。这项工作精确识别并量化了基于氧化物半导体和电容器的6T1C突触器件中的干扰效应,其耐久性和变化已得到验证,但随着器件缩小会遇到更严重的干扰效应。通过阐明干扰机制,提出了三种简单的操作方案来减轻这些影响,并通过器件阵列测量验证了其有效性。此外,为了评估大规模阵列中的学习可行性,通过将突触阵列映射到CIFAR-10数据集的卷积神经网络进行实时干扰感知训练模拟。即使在强化干扰下,使用50fF的单元电容器尺寸,也能实现与软件等效的精度,这与动态随机存取存储器相当。结合耐久性和变化的固有优势,这种方法为基于6T1C突触阵列的硬件深度学习提供了一种实用解决方案。