Redox-based random-access memory (ReRAM) has the potential to successfully address the technological barriers that today's memory technologies face. One of its promising features is its fast switching speed down to 50 ps. Identifying the limiting process of the switching speed is, however, difficult. At sub-nanosecond timescales three candidates are being discussed: An intrinsic limitation, being the migration of mobile donor ions, e.g., oxygen vacancies, the heating time, and its electrical charging time. Usually, coplanar waveguides (CPW) are used to bring the electrical stimuli to the device. Based on the data of previous publications, we show, that the rise time of the effective electrical stimulus is mainly responsible for limiting the switching speed at the sub-nanosecond timescale. For this purpose, frequency domain measurements up to 40 GHz were conducted on three Pt\TaO x \Ta devices with different sizes. By multiplying the obtained scattering parameters of these devices with the Fourier transform of the incoming signal, and building the inverse Fourier transform of this product, the voltage at the ReRAM device can be determined. Finally, the rise time of the voltage at the ReRAM device is calculated, which is a measure to the electrical charging time. It was shown that this rise time amounts to 2.5 ns for the largest device, which is significantly slower than the pulse generator's rise time. Reducing the device's rise time down to 66 ps is possible, but requires smaller features sizes and other optimizations, which we summarize in this paper.

中文翻译：

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确定 ReRAM 器件的充电速度限制


基于氧化还原的随机存取存储器 (ReRAM) 有潜力成功解决当今存储技术面临的技术障碍。其最有前途的特性之一是其低至 50 ps 的快速开关速度。然而，识别开关速度的限制过程很困难。在亚纳秒时间尺度上，正在讨论三个候选者： 固有限制，即移动供体离子的迁移，例如氧空位、加热时间及其充电时间。通常，共面波导 (CPW) 用于将电刺激引入设备。根据之前出版物的数据，我们表明，有效电刺激的上升时间主要负责限制亚纳秒时间尺度的开关速度。为此，在三个不同尺寸的 Pt\TaO x \Ta 器件上进行了高达 40 GHz 的频域测量。通过将这些器件获得的散射参数与输入信号的傅里叶变换相乘，并构建该乘积的傅里叶逆变换，可以确定 ReRAM 器件上的电压。最后，计算 ReRAM 器件电压的上升时间，这是充电时间的衡量标准。结果表明，最大器件的上升时间为 2.5 ns，明显慢于脉冲发生器的上升时间。将器件的上升时间降低至 66 ps 是可能的，但需要更小的特征尺寸和其他优化，我们在本文中对此进行了总结。