Department of Electronic Materials Engineering, Research School of Physics, The Australian National, University, Canberra, ACT 2601, Australia.
Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Perth 6009, Australia.
Nanoscale. 2023 Apr 27;15(16):7559-7565. doi: 10.1039/d3nr00173c.
Volatile threshold switching and current-controlled negative differential resistance (NDR) in metal-oxide-metal (MOM) devices result from thermally driven conductivity changes induced by local Joule heating and are therefore influenced by the thermal properties of the device-structure. In this study, we investigate the effect of the metal electrodes on the threshold switching response of NbO-based cross-point devices. The electroforming and switching characteristics are shown to be strongly influenced by the thickness and thermal conductivity of the top-electrode due to its effect on heat loss from the NbO film. Specifically, we demonstrate a 40% reduction in threshold voltage and a 75% reduction in threshold power as the thickness of the top Au electrode is reduced from 125 nm to 25 nm, and a 24% reduction in threshold voltage and 64% reduction in threshold power when the Au electrode is replaced by a Pt electrode of the same thickness of NbO film, due to its lower thermal conductivity. Lumped element and finite element modelling of the devices show that these improvements are due to a reduction in heat loss to the electrodes, which is dominated by lateral heat flow within the electrode. These results clearly demonstrate the importance of the electrodes in determining the electroforming and threshold switching characteristics of MOM cross point devices.
金属-氧化物-金属（MOM）器件中的挥发性阈值切换和电流控制的负微分电阻（NDR）是由局部焦耳加热引起的热驱动电导率变化引起的，因此受器件结构的热性能影响。在这项研究中，我们研究了金属电极对基于 NbO 的交叉点器件的阈值切换响应的影响。电成形和开关特性强烈受到顶电极的厚度和热导率的影响，因为它会影响 NbO 薄膜的热损失。具体来说，我们证明了当顶 Au 电极的厚度从 125nm 减小到 25nm 时，阈值电压降低了 40%，阈值功率降低了 75%，而当 Au 电极被厚度相同的 Pt 电极取代时，阈值电压降低了 24%，阈值功率降低了 64%，这是因为 Pt 的热导率较低。器件的集总元件和有限元建模表明，这些改进是由于向电极的热损失减少所致，而电极的热损失主要由电极内的横向热流决定。这些结果清楚地表明了电极在确定 MOM 交叉点器件的电成形和阈值切换特性方面的重要性。
