A next-generation semiconductor technology that can dramatically reduce data-processing power and chip area in space satellite communications and 6G network environments has been developed by a Korean research team. The technology is expected to fundamentally resolve the standby power consumption and signal-processing delay problems that have been cited as limitations of existing high-frequency communication systems.
The Ulsan National Institute of Science and Technology (UNIST) announced Monday that a team led by Professor Kim Myung-soo of the Department of Electrical and Electronic Engineering has developed a multifunctional "memristor" semiconductor device based on an oxidized two-dimensional semiconductor material.
Next-generation 6G and satellite communication technologies that transmit ultra-high-speed, large-capacity data utilize high frequency bands, making the role of the "RF switch" that controls the path of high-frequency signals absolutely essential. However, in satellite communications that must operate on limited energy such as solar power, or in edge AI equipment with severe power and space constraints, the high operating power and complex processes of existing switches have posed a significant burden. In addition, the conventional method of converting analog high-frequency signals received through antennas into digital form and computing them in a separate processor added to power consumption and delay.
The research team solved these challenges by fabricating a multifunctional memristor device, applying a 400°C thermal oxidation process to molybdenum disulfide (MoS2), a two-dimensional semiconductor material. A memristor is a device that combines the properties of memory and resistance, with the ability to remember how well current flows.
The newly developed memristor device simultaneously performs the roles of an "RF switch" that controls the path of high-frequency communication signals and a "computing device" that processes data, all on a single platform. It dramatically reduces chip area and substantially lowers the power consumption and delay that occur in the process of converting and moving signals to other circuits.
In particular, it features "non-volatility," meaning that once its state is switched, the ON and OFF states are maintained even when the power is cut off. No continuous standby power consumption occurs at all. The switching energy required to turn the device on or off once is very low, at the level of 140 pJ (picojoules, 10⁻¹²), and the operating power to change states is also just under 1 mW (milliwatt).
Its stability and high-frequency performance are also outstanding. Once changed, the resistance state is maintained for more than 40,000 seconds, and it demonstrated stability over more than 1,000 repeated operations. The switching performance in the high-frequency bands used for ultra-high-speed communications has been verified through experiments up to 67 GHz, and the calculated cutoff frequency reaches 33.2 THz.
In addition, the research team verified an in-memory matrix computation function through simulation using a crossbar circuit in which multiple devices are arranged like a checkerboard. The resistance value of each device serves as a weight in matrix calculations, confirming that complex operations such as 1024-QAM signal demodulation and multiple-input multiple-output (MIMO) signal recovery can be performed independently without separate analog-to-digital conversion.
Son Ju-ho, the lead author and researcher, explained, "This is a technology that fundamentally solves the standby power consumption and signal loss problems of existing commercial semiconductor high-frequency switches." He added, "Even compared to next-generation phase-change memory (PCM) or microelectromechanical systems (MEMS), it has superior competitiveness in terms of energy efficiency, ultra-high-frequency operating speed, and miniaturization."
Professor Kim Myung-soo stressed, "We have demonstrated that an oxidized 2D semiconductor-based memristor can be used not only as a high-performance millimeter-wave RF switch but also as in-memory matrix computing hardware needed for 6G signal processing." He added, "Having secured non-volatility, low power, and high-frequency characteristics all at once, it will greatly contribute to the miniaturization and improved energy efficiency of satellite communications, radar, and defense radio-wave control systems in the future."
Meanwhile, this research was conducted with support from the National Research Foundation of Korea under the Ministry of Science and ICT, as well as the Institute for Information & Communications Technology Planning & Evaluation's Outstanding Young Researcher program and the Space-K BIG project. The research results were published online on June 6 in Advanced Functional Materials, a world-renowned journal in the field of materials.
