Innovative Method by Hanyang University Researchers Overcomes Challenges in Semiconductor Crystal Formation

Revolutionary Control Over Semiconductor Crystal Formation

Researchers at Hanyang University, located in Gyeonggi-do, South Korea, have made significant strides in semiconductor manufacturing by introducing an innovative method for controlling the initiation of crystal formation. This breakthrough is vital for the production of two-dimensional (2D) semiconductors, which have the potential to power next-generation electronic devices.

The complexity of managing where crystals begin to grow has historically posed challenges in creating precise electronic structures. Traditional area-selective growth methods have often failed to ensure reliable nucleation in designated regions, leading to difficulties in producing large, uniform single crystals necessary for efficient electronic applications.

In a recent study published in Nature, the team has introduced a novel technique known as etching-flux-mediated single-centred nucleation (EF-SCN). This method effectively controls where and how semiconductor crystals, specifically molybdenum disulfide (MoS₂), are allowed to form through a combination of unique temperature management and pattern design. The researchers utilized a hafnium oxide (HfO₂) barrier to release oxygen when heated to 750°C, which plays a crucial role in shaping the nucleation process.

By etching the surrounding areas with this oxygen flow, the method suppresses unwanted nucleation at the boundaries of the patterns, thereby promoting the formation of single crystals centrally within the designated regions. Their results demonstrated impressive consistency, yielding over 99% single-crystal growth across a system of 400 site arrays.

In pursuit of further advancements, the researchers successfully adapted their method to facilitate crystal growth at lower temperatures by substituting HfO₂ with zirconium dioxide. This allowed for the creation of triangular single-crystal MoS₂ domains at temperatures as low as 430°C, offering more flexibility in production processes.

The research team meticulously explored the growth conditions, discovering that the flow rate of diethyl sulfide, which supplies sulfur, is critical in regulating the number of crystal nuclei formed. They found that an optimal balance was essential; insufficient flow could halt nucleation altogether, while excessive flow led to multiple crystals forming in a single area. Likewise, adjusting the molybdenum precursor flow rate impacted the extent of crystal expansion, allowing for the production of larger structures tailored for electronic applications, including transistors.

The researchers successfully produced MoS₂ crystals up to 8 micrometers across, with single-crystal films managing to fill 10-micrometer growth areas effectively. The application of this newly developed EF-SCN method across a 2-centimeter substrate resulted in an exceptional crystallization yield.

To further assess the utility of their crystals, the team constructed field-effect transistors incorporating the MoS₂, achieving a remarkable field-effect mobility of 117 cm²/V·s. They even integrated multiple transistors within a single crystal, ensuring only a 7.8% variation in electron mobility. These results highlight the immense potential for crafting denser electronic circuits that promise more consistent performance than traditional methods.

Professor Woo-Hee Kim, the lead researcher, stated, "This approach surpasses conventional area-selective growth techniques, offering a reproducible method for single-crystal growth. It allows for strategic programming of nucleation positions and designs, alongside promising device integration possibilities."

With the EF-SCN method in place, Hanyang University positions itself at the forefront of semiconductor research, aiming to enhance the future landscape of electronic device production. As the battle against conventional manufacturing constraints continues, this innovative approach presents exciting implications for the efficiency of 2D semiconductor technologies.

For further details, the original research paper titled Spatially deterministic nucleation of 2D semiconductors by etching flux can be accessed in Nature, DOI: 10.1038/s41586-026-11095-1.