UNIST-University of Minnesota, using atomic layer deposition
Success in fabricating ultra-fine semiconductor electrode patterns
Easy to manufacture, no need for expensive beam process


Semiconductor chips contain up to billions of transistors and diodes. These microscopic elements exist as patterns drawn into multiple layers of material. However, manufacturing these patterns requires an expensive process of drawing the shape with a beam.

Accordingly, a research team led by Professor Namgung Seon of the Department of Physics at Ulsan National Institute of Science and Technology (UNIST) announced on the 24th that, in collaboration with a research team from the University of Minnesota, they have developed a technology to manufacture semiconductor patterns using only atomic layer deposition, a process that involves layering materials thinly multiple times. This research was published online in the nanomaterials journal ACS Nano on February 24th and is awaiting official publication.

Atomic layer deposition is simpler and cheaper than beam-based techniques, and the channel width, which is the spacing between electrodes, can be changed to nanometers by depositing the number of atomic layers. It is also advantageous for the production of new concept semiconductor devices using two-dimensional semiconductor materials instead of silicon.

Using the technology developed by the joint research team, they created ultra-fine "semiconductor electrodes" with channels of less than 10 nanometers and a two-dimensional transistor. They deposited electrodes, insulators, and electrodes in that order onto a substrate to create a nano-gap pattern. When this was peeled off the substrate and flipped over, an electrode pattern was completed with the distance between the electrodes being equal to the thickness of the insulating layer. The electrode surfaces were immediately separated from the substrate, resulting in a smooth surface, making them suitable for stacking two-dimensional semiconductor materials on top of the electrodes to create devices.

The joint research team also applied this to a transistor-based photodetector. The strong electric field between the ultra-fine transistor electrodes effectively separated the charged particles generated by light, enhancing detection performance. A photodetector is a device that detects light in the form of an electric current.

Professor Namgung Seon said about this technology, “It is a technology that mass-produces uniform nanometer-scale electrode structures using the existing semiconductor process technology, atomic layer deposition,” and “It will be useful for miniaturizing semiconductor structures, developing ultra-small optical communication modules, and developing optical semiconductor chips.”