Korean Scientists have developed a new technology for producing molybdenum disulfide (MoS₂), a promising next-generation semiconductor. This technology uses plasma etching to create defect-free MoS₂ layers on a large scale (4 inches).
The researchers were able to control the thickness of the MoS₂ layers at the atomic level, overcoming the limitations of traditional silicon-based semiconductors.
The joint research team led by Hyeong-U Kim, Senior Researcher of the Department of Plasma Engineering at the Korea Institute of Machinery and Materials (KIMM), an institute under the jurisdiction of the Ministry of Science and ICT, and Professor Kim Tae-sung of Sungkyunkwan University, announced that the team has succeeded in developing the “Large-scale (4-inch) atomic layer etching technology for MoS₂,a next-generation semiconductor, using plasma-based reactive ion etcher (RIE) equipment.”
This research, in which Senior Researcher Muyoung Kim and Post-doctoral Researcher Changmin Kim of KIMM participated as co-first authors, has been published as the cover article of the February 2023 edition of “Chemistry of Materials,” a renowned international academic journal.
MoS₂ has unique properties that make it suitable for future semiconductors. Unlike silicon, MoS₂ can control the movement of electrons without tunneling effects, even at extremely thin thicknesses of just 1 nanometer. However, the mass production of MoS₂-based semiconductors has been challenging due to difficulties in achieving uniformity on a large scale.
The research team developed a process combining plasma-enhanced chemical vapor deposition (PECVD) and reactive ion etching (RIE) to precisely etch MoS₂ layers in a large-scale (4-inch) format. This breakthrough paves the way for the industrial use of MoS₂-based semiconductors.
Plasma etching has been recognized as a promising technology, but it has had limitations in terms of impurities remaining on the semiconductor surface after the process. The researchers overcame this challenge by using a computational screening system based on density functional theory (DFT) to optimize the plasma process.
This system allowed them to identify the best gas mixture (Ar + O₂ + CF₄) for achieving both atomic-level precision and high purity in the MoS₂ layers. This computational approach significantly reduces development time and costs compared to traditional experimental methods.
“To overcome the limitations of integration, it is necessary to develop processes where even single-atomic layers are controllable, as demonstrated in our latest research. Hence, many studies have been conducted since around a decade ago," said Professor Kim. "However, before our latest study, no researcher has been able to demonstrate the possibility of etching atomic layers uniformly and reproducibly in a large scale. Our research outcome is expected to help the next-generation 2D semiconductor industry in the non-memory sector to find a new breakthrough in the future.”
