Daegu Gyeongbuk Institute of Science and Technology (DGIST) said on the 21st that a research team led by Professor Kwon Hyuk-jun of the Department of Electrical, Electronic and Computer Engineering has developed a new technology that changes a semiconductor's conduction property with a single laser process. Because it can replace complex, lengthy steps with a single process, it is seen as a way to significantly boost semiconductor manufacturing efficiency.
Semiconductors are divided into "n-type" and "p-type" depending on the main charge carriers that conduct current. In n-type semiconductors, negatively charged electrons (e⁻) move to conduct current, while in p-type semiconductors, holes (h⁺), the absence of electrons, move to create current. Because electronic devices such as smartphones and computers use "CMOS" circuits in which the two work together, implementing both n-type and p-type semiconductors is essential.
The team focused on titanium oxide (TiO₂), long regarded as an "ideal semiconductor material." The substance is non-toxic, abundant, and resistant to heat and chemical reactions. However, because its crystal structure is too stable, holes, the absence of electrons, do not readily form, limiting it to operating only as an n-type semiconductor. In other words, its performance is excellent, but only half of the circuit could be used.
To solve this, the team developed "LODI (Laser-Induced Oxidation and Doping Integration)" technology. It simultaneously carries out, with a single laser exposure, two steps—oxidation, in which a metal bonds with oxygen to form a new substance, and doping, in which other atoms infiltrate the material to alter its electrical properties.
The researchers covered a thin titanium (Ti) metal film with an aluminum oxide (Al₂O₃) layer and irradiated it with a laser for a few seconds. As a result, the titanium bonded with oxygen and transformed into titanium oxide, while aluminum ions simultaneously infiltrated the interior. This disrupted the electron balance, creating holes, and ultimately produced a p-type semiconductor in which holes, instead of electrons, conduct current.
Previously, converting titanium oxide to p-type required complex processes such as heat treatment at high temperatures for dozens of hours or ion implantation in a vacuum. Such methods involved expensive equipment and long processing times, posing major hurdles to commercialization.
But LODI can achieve the same effect with a single laser in just a few seconds. Because oxidation, doping, and even fine pattern formation occur at once, it is being evaluated as a next-generation semiconductor manufacturing technology that can drastically cut manufacturing time and expense.
Kwon said, "We have developed a fundamental technology that can precisely control the conduction properties of oxide semiconductors," adding, "It will serve as an important foundation for the development of next-generation, highly integrated and highly reliable semiconductor devices."
The findings were published as a cover paper in the international journal "Small" on the 2nd.
References
Small (2025), DOI: https://doi.org/10.1002/smll.70300