Akkili Viswanath G, Yoon Jongchan, Shin Kihyun, Jeong Sanghyun, Moon Ji-Yun, Choi Jun-Hui, Kim Seung-Il, Patil Ashish A, Aziadzo Frederick, Kim Jeongbeen, Kim Suhyeon, Shin Dong-Wook, Wi Jung-Sub, Cho Hoon-Hwe, Park Joon Sik, Kim Eui-Tae, Kim Dong-Eun, Heo Jaeyeong, Henkelman Graeme, Novoselov Kostya S, Chung Choong-Heui, Lee Jae-Hyun, Lee Zonghoon, Lee Sangyeob
Department of Materials Science and Engineering, Hanbat National University, Daejeon 34158, Republic of Korea.
Center for Multidimensional Carbon Materials, Institute for Basic Science and Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea.
ACS Nano. 2025 Jan 14;19(1):1056-1069. doi: 10.1021/acsnano.4c12780. Epub 2024 Dec 31.
Ultrasmall-scale semiconductor devices (≤5 nm) are advancing technologies, such as artificial intelligence and the Internet of Things. However, the further scaling of these devices poses critical challenges, such as interface properties and oxide quality, particularly at the high-/semiconductor interface in metal-oxide-semiconductor (MOS) devices. Existing interlayer (IL) methods, typically exceeding 1 nm thickness, are unsuitable for ultrasmall-scale devices. Here, we propose a one-atom-thick amorphous carbon monolayer (ACM) as the IL to address these issues for MOS devices. ACM is disordered, randomly arranged, and short of long-range periodicity with hybridized carbon network, offering impermeability, van der Waals (vdW) bonding, insulating behavior, and effective seeding layer. With these advantages, we have utilized ACM vdW IL (vIL) in AlO/H-Ge MOS capacitors. The interface trap density was suppressed by ∼2 orders of magnitude to 7.21 × 10 cm eV, with no frequency-dependent flat band shift. The slow trap density is decreased to 2 orders of magnitude, and the - hysteresis width is minimized by >75%, indicating enhanced oxide quality. These results are supported by high-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy analysis, confirming the creation of an atomically well-defined interface in the AlO/H-Ge heterojunction with ACM vIL, even under high-temperature annealing conditions. Density functional theory calculations further clarify that ACM vIL preserves the hydrogen-passivated Ge surface without altering its electronic band structure. These results demonstrate that ACM vIL effectively improves the interface properties and enhances the oxide quality, enabling further advancements in ultrasmall-scale MOS devices.
超小尺寸半导体器件（≤5纳米）推动着人工智能和物联网等技术的发展。然而，这些器件的进一步缩小带来了严峻挑战，比如界面特性和氧化物质量，尤其是在金属氧化物半导体（MOS）器件的高/半导体界面处。现有的层间（IL）方法，其厚度通常超过1纳米，不适用于超小尺寸器件。在此，我们提出一种单原子厚的非晶碳单层（ACM）作为层间介质来解决MOS器件的这些问题。ACM无序、随机排列且缺乏具有杂化碳网络的长程周期性，具有不透性、范德华（vdW）键合、绝缘行为以及有效的籽晶层。凭借这些优势，我们已在AlO/H-Ge MOS电容器中使用了ACM vdW层间介质（vIL）。界面陷阱密度被抑制了约2个数量级，降至7.21×10厘米电子伏特，且不存在频率相关的平带位移。慢陷阱密度降低了2个数量级，滞后宽度最小化超过75%，表明氧化物质量得到了提升。这些结果得到了高分辨率透射电子显微镜和能量色散X射线光谱分析的支持，证实了即使在高温退火条件下，在具有ACM vIL的AlO/H-Ge异质结中形成了原子级清晰定义的界面。密度泛函理论计算进一步阐明，ACM vIL保留了氢钝化的Ge表面，而不改变其电子能带结构。这些结果表明，ACM vIL有效地改善了界面特性并提升了氧化物质量，推动了超小尺寸MOS器件的进一步发展。
