Korean researchers gain control over where 2D semiconductor crystals start

The science ministry said Thursday that a Korean joint research team has developed a way to control exactly where a two-dimensional semiconductor crystal begins to grow, a step toward stacking next-generation AI chips. The work, led by KAIST professor Kang Ki-beom with UNIST, Hanyang University and TDS Innovation, was published in Nature.

The team used oxygen released from an oxide barrier made of hafnium oxide among other materials to suppress the formation of crystal nuclei in molybdenum disulfide. That suppression is strongest near the edge of the barrier and weakest at the centre, pushing a single nucleus to form in the middle of the growth region. The crystal then spreads sideways without meeting others, avoiding the misaligned atomic boundaries that disrupt electron flow.

The researchers reported a single molybdenum disulfide crystal at the centre of more than 99 percent of 400 experimental patterns. Earlier selective-growth methods could confine a crystal to a chosen area, but where the nucleus would appear inside that area was left to chance.

Two-dimensional materials, only a few atomic layers thick, are seen as a way to build AI chips by stacking semiconductors on top of existing logic circuits, raising performance and cutting power use.

"Through this research we have confirmed a new possibility for precisely controlling where crystals begin during the growth of two-dimensional semiconductors," Kang said. "Going forward, we intend to apply this underlying technology to actual semiconductor manufacturing processes and ultimately develop it into next-generation AI semiconductor technology that vertically integrates logic and memory."

The work was carried out with support from the Ministry of Science and ICT's individual basic research programme and its nanomaterials technology development programme.

"This achievement is a case in which basic research into how semiconductor materials form, combined with the development of underlying technology, has suggested a new solution for semiconductor manufacturing processes," said Kim Sung-soo, the ministry's director-general for research and development policy. He said the ministry would continue to support researchers' creative work.