KAIST develops low-temperature semiconductor stacking technology that avoids layer damage

Researchers have developed a technology that lowers the semiconductor growth process — which previously required temperatures of several hundred degrees Celsius — to just 150 degrees Celsius, allowing new semiconductor layers to be stacked on two-dimensional materials without damage.

KAIST announced Monday that a research team led by professor Seo Jun-ki of the Department of Chemical and Biomolecular Engineering developed the new semiconductor manufacturing technology using atomic layer deposition, in collaboration with a team led by professor Song Bong-geun of Hanyang University and a team led by professor Imo Han of Rice University in the United States.

The research team focused on van der Waals materials, which have drawn attention as promising two-dimensional semiconductor materials. Because different materials can be freely layered on top of one another, van der Waals materials are regarded as a key component for next-generation AI semiconductors and ultra-low-power semiconductors.

However, the highly stable surface of van der Waals materials has made it difficult to grow new semiconductor layers in a controlled, orderly direction. At lower temperatures in particular, atoms tend to scatter and grow unevenly, making it hard to produce high-performance semiconductors.

The team developed a new method in which a tellurium (Te)-containing precursor — tellurium being a next-generation semiconductor material — moves freely across the surface and self-locates the most stable positions to form a thin film.

Using this approach, the team achieved epitaxial growth on van der Waals materials via atomic layer deposition (ALD) at 150 degrees Celsius. In epitaxial growth, a new semiconductor grows with atomic-level precision by following the crystal structure of the underlying layer — analogous to laying bricks not haphazardly but uniformly in the same direction, which allows electricity to flow more efficiently and improves semiconductor performance. Van der Waals materials are next-generation two-dimensional semiconductor materials composed of multiple stacked atomic layers.

The team also confirmed that the technology can be applied to a range of van der Waals materials, including tungsten diselenide (WSe₂), molybdenum disulfide (MoS₂), rhenium diselenide (ReSe₂) and mica. The results show the technique is not limited to a single material but can be broadly applied across multiple types of next-generation semiconductor materials.

Using the semiconductors produced through this method, the team also fabricated transistors — the core components that control current flow in semiconductors — and optoelectronic devices, which detect or emit light.

"Achieving epitaxial growth at 150 degrees Celsius means we can grow highly crystalline, orientation-controlled thin films while significantly reducing thermal stress," professor Seo said. "This demonstrates the potential to integrate new functional thin films on top of already-formed semiconductor structures with minimal additional damage, pointing toward future applications in next-generation heterogeneous semiconductor integration processes."

The findings were published in the international journal Science Advances on July 24.