Kim Juhee, Song Woochan, Park Jeonghyeon, Kim Seungkun, Kim Hyejin, Kim Jong Kyu, Kim Seyoung
Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
Sci Rep. 2025 Jul 1;15(1):21111. doi: 10.1038/s41598-025-06671-w.
In neuromorphic computing, which overcomes the limitations of the von Neumann architecture, resistive processing units performing data processing and memory storage simultaneously have been widely researched. Among analog resistive devices, electrochemical random-access memories (ECRAMs) have drawn significant attention, which operate via ion movements to control channel conductance. Despite their promising switching characteristics, the contact resistance between Tungsten oxide (WO) channel and metal electrodes has not been studied yet. In this study, we fabricate transmission line model devices to investigate the contact resistance between WO and the metals of Tungsten (W), Molybdenum (Mo), and Nickel (Ni). Results show that W exhibits the lowest contact resistance with WO, followed by Ni and Mo. We confirm that W and Mo show Ohmic contacts, whereas Ni reveals a Schottky contact with a Schottky barrier height of 118 meV. Moreover, we demonstrate Mo only forms a metal oxidation layer of 9 nm at the interface between WO and Mo. Finally, we present the trend of contact resistivity depending on WO channel resistivity under different channel conductance values of the W contact. These findings provide insights into contact resistance of WO-based ECRAMs, suggesting that W is the most suitable contact material for achieving high performance.
在克服冯·诺依曼架构局限性的神经形态计算中，能够同时执行数据处理和内存存储的电阻式处理单元已得到广泛研究。在模拟电阻式器件中，通过离子移动来控制沟道电导的电化学随机存取存储器（ECRAM）受到了极大关注。尽管它们具有很有前景的开关特性，但氧化钨（WO）沟道与金属电极之间的接触电阻尚未得到研究。在本研究中，我们制作了传输线模型器件，以研究WO与钨（W）、钼（Mo）和镍（Ni）等金属之间的接触电阻。结果表明，W与WO的接触电阻最低，其次是Ni和Mo。我们证实W和Mo呈现欧姆接触，而Ni显示出肖特基接触，肖特基势垒高度为118毫电子伏特。此外，我们证明Mo仅在WO与Mo的界面处形成了一个9纳米厚的金属氧化层。最后，我们展示了在W接触的不同沟道电导值下，接触电阻率随WO沟道电阻率的变化趋势。这些发现为基于WO的ECRAM的接触电阻提供了见解，表明W是实现高性能的最合适接触材料。
