Unanticipated Polarity Shift in Edge-Contacted Tungsten-Based 2D Transition Metal Dichalcogenide Transistors
Unanticipated Polarity Shift in Edge-Contacted Tungsten-Based 2D Transition Metal Dichalcogenide Transistors
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DOI：
10.1109/led.2021.3106286
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发表时间：
2021-10-01
影响因子：
4.9
通讯作者：
Franklin, Aaron D.
中科院分区：
文献类型：
--
作者：
Abuzaid, Hattan;Cheng, Zhihui;Franklin, Aaron D.
在过渡金属二硫属化物 (TMD) 晶体管中创建金属边缘接触是推进未来技术节点晶体管小型化的一条有前途的途径。目前的实验演示几乎完全集中于 MoS2 作为通道材料。在这里，我们使用集成在电子束蒸发室中的会聚 Ar+ 离子束源进行原位处理，创建边缘接触的 WSe2 和 WS2 晶体管。与显示 p 型传导的 Ti-WS2 器件的顶部接触行为相比，观察到了意想不到的极性变化。同时，三种不同的金属接触材料在 WSe2 上产生了可比的 p 支链主导性能。透射电子显微镜 (TEM) 成像和能量色散光谱 (EDS) 分析表明，即使基材被过度蚀刻，金属触点下方仍存在 W 残留层（以及较小程度的硫族原子）。这些图像呈现出物理上纯粹的边缘界面。这种有趣的蚀刻效应可能会对钨基边缘接触 TMD 晶体管的设计产生重大影响。
Creating metal edge contacts in transition metal dichalcogenide (TMD) transistors is a promising path to advance transistor miniaturization for future technology nodes. Current experimental demonstrations nearly exclusively focus on MoS2 as the channel material. Here, we create edge-contacted WSe2 and WS2 transistors using a convergent Ar+ ion beam source integrated within an e-beam evaporator chamber for in-situ processing. An unanticipated polarity shift was observed compared to top-contact behavior for Ti-WS2 devices, which displayed p-type conduction. Meanwhile, three distinct metal contact materials yielded comparable p-branch-dominant performance on WSe2. Transmission electron microscope (TEM) imaging with energy dispersive spectroscopy (EDS) analysis indicated the existence of a residual layer of W (and chalcogen atoms to a lesser extent) beneath the metal contacts, even though the substrate was over-etched. The images presented a physically pure edge interface. This intriguing etching effect could carry significant implications for the design of tungsten-based, edge-contacted TMD transistors.