Large-scale atomic layer etching technology for MoS2 developed

A groundbreaking advancement has been made in the field of semiconductor technology. A joint research team led by Hyeong-U Kim, Senior Researcher at the Korea Institute of Machinery and Materials (KIMM), and Professor Taesung Kim of Sungkyunkwan University, has successfully developed a large-scale atomic layer etching technology for molybdenum disulfide (MoS2), a next-generation two-dimensional semiconductor. This achievement has the potential to revolutionize the industrial supply of MoS2.

In the pursuit of ever-shrinking silicon-based semiconductors, it has become crucial to control the manufacturing process at the atomic level. However, the accumulation of atomic layers in silicon-based semiconductors poses challenges due to the tunneling effect. Therefore, the development of alternative materials for future-generation semiconductors has become imperative.

MoS2 has emerged as a promising candidate for overcoming the limitations of silicon-based semiconductors. It enables stable electron movement without the tunneling effect, even in structures as thin as 1 nanometer. Despite its superior properties, the mass production of MoS2-based semiconductors has remained at the laboratory research stage due to the difficulty of achieving uniformity on a large scale.

The research team has now overcome this hurdle by developing a process that utilizes plasma-enhanced chemical vapor deposition (PECVD) and reactive ion etching (RIE) to etch large-scale (4-inch) MoS2 to the desired atomic layer thickness. This breakthrough opens up new possibilities for the industrial utilization of MoS2-based semiconductors.

Plasma etching has long been considered a potential solution to surpass the limitations of conventional etching processes. However, one major drawback of plasma etching is the presence of impurities, such as fluorine, on the semiconductor surface after the process. To address this issue, the research team employed a computational screening system based on density functional theory (DFT). This system simulated the surface reaction of candidate gases and identified the optimal gas mixture for achieving high process quality. By reducing the reliance on time-consuming experimental methods, the screening system significantly shortened the development time and cost of the plasma process.

The team’s senior researcher, Hyeong-U Kim, emphasized the importance of precise line width control in the foundry process, particularly in non-memory sectors such as AI, IoT, and self-driving technologies. He stated that the ability to control single-atomic layers is essential for overcoming integration limitations. Previous studies have attempted to achieve this control, but no researcher has demonstrated the uniform and reproducible etching of atomic layers on a large scale until now. This breakthrough is expected to pave the way for advancements in the next-generation 2D semiconductor industry, particularly in the non-memory sector.

The research findings have been published as the cover article in the February 2023 edition of Chemistry of Materials, solidifying their significance in the field of semiconductor technology.

Source: National Research Council of Science & Technology

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