Tag Archives: Daegu Gyeongbuk Institute of Science and Technology (DGIST)

As researchers build high-yield memristor chips, brain-inspired AI moves closer

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This November 7, 2025 news item on Nanowerk highlights research into memristors from Daegu Gyeongbuk Institute of Science and Technology (DGIST), Note: Links have been removed,

A research team at DGIST in South Korea has taken a major step toward building chips that work more like the human brain. Led by Professor Sanghyeon Choi from the Department of Electrical Engineering and Computer Science, the group has developed a highly integrated memristor device at full wafer scale, a milestone for next-generation AI hardware (Nature Communications, “Wafer-scale fabrication of memristive passive crossbar circuits for brain-scale neuromorphic computing”).

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A November 28, 2025 Daegu Gyeongbuk Institute of Science and Technology (DGIST) press release (also on EurekAlert but published November 4, 2025), which originated the news item, announced its ‘wafer-scale memristor’ and its possible impact on neuromorphic (brain-like) computing,

A research team led by Professor Sanghyeon Choi from the Department of Electrical Engineering and Computer Science at DGIST (President Kunwoo Lee) successfully developed the “memristor,” which is gaining recognition as a next-generation semiconductor device, through mass-integration at the wafer scale. This study proposes a new technological platform for implementing a highly integrated AI semiconductor replicating the human brain, overcoming the limitations of conventional semiconductors.

The human brain contains about 100 billion neurons and around 100 trillion synapses, allowing it to store and process enormous amounts of information within a compact space. Next-generation AI research aims to develop “brain-like AI chips” that replicate this structure. Yet, current AI semiconductors remain far less efficient than the human brain, largely because of their intricate circuitry and substantial power requirements.

The memristor is an emerging alternative option that can overcome these limitations. As a semiconductor device capable of remembering the amount of current flowed, it simultaneously executes memory and computation tasks. Owing to its simple architecture, the circuit can be configured with a much higher density than typical semiconductors. Specifically, an arrangement in a crossbar format enables dozens of times more information to be stored in the same area, compared to SRAM.

However, memristor integration technology has so far been limited to small-scale experimental demonstrations. The main reasons include process complexity, low yield (product completion rate), voltage loss, and current leakage, all of which have hindered its expansion to large-scale wafer production.

Thus, Professor Choi and his team carried out joint research with Dr. Dmitri Strukov’s group at UC Santa Barbara [University of California at Santa Barbara] and introduced a new approach of “co-designing material, component, circuit, and algorithm.” This method enabled the implementation of a memristor crossbar circuit that achieved an approximately 95% yield on a 4-inch wafer without requiring a complex fabrication process.

Furthermore, the research team successfully demonstrated a 3D vertical stacking structure. This signifies the possibility of a memristor-based circuit being expanded into a large-scale AI computation system in the future.

In addition, when a spiking neural network was applied based on the proposed technology, notable efficiency and stable execution were confirmed in actual AI computation.

Professor Choi stated, “This study proposed a method for improving memristor integration technology, which had been limited in the past” and added, “We are expecting it to lead to the development of a next-generation semiconductor platform in the future.”

This study was supported by the U.S. National Science Foundation, Industrial Innovation Talent Growth Support Program of the Korea Institute for Advancement of Technology, and Engineering Academic Research Support Program of the National Research Foundation of Korea’s Science. The research, led by Professor Choi of DGIST as both the first and corresponding author, with Professor Dmitri Strukov of UC Santa Barbara as a co-author, was published in October in the prestigious multidisciplinary journal “Nature Communications.”

Here’s a link to and a citation for the paper,

Wafer-scale fabrication of memristive passive crossbar circuits for brain-scale neuromorphic computing by Sanghyeon Choi, Sai Sukruth Bezugam, Tinish Bhattacharya, Dongseok Kwon & Dmitri B. Strukov. Nature Communications volume 16, Article number: 8757 (2025) Published: 01 October 2025 Version of record: 01 October 2025 DOI: https://doi.org/10.1038/s41467-025-63831-2

This paper is open access.

Artificial synapse based on tantalum oxide from Korean researchers

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This memristor story comes from South Korea as we progress on the way to neuromorphic computing (brainlike computing). A Sept. 7, 2018 news item on ScienceDaily makes the announcement,

A research team led by Director Myoung-Jae Lee from the Intelligent Devices and Systems Research Group at DGIST (Daegu Gyeongbuk Institute of Science and Technology) has succeeded in developing an artificial synaptic device that mimics the function of the nerve cells (neurons) and synapses that are response for memory in human brains. [sic]

Synapses are where axons and dendrites meet so that neurons in the human brain can send and receive nerve signals; there are known to be hundreds of trillions of synapses in the human brain.

This chemical synapse information transfer system, which transfers information from the brain, can handle high-level parallel arithmetic with very little energy, so research on artificial synaptic devices, which mimic the biological function of a synapse, is under way worldwide.

Dr. Lee’s research team, through joint research with teams led by Professor Gyeong-Su Park from Seoul National University; Professor Sung Kyu Park from Chung-ang University; and Professor Hyunsang Hwang from Pohang University of Science and Technology (POSTEC), developed a high-reliability artificial synaptic device with multiple values by structuring tantalum oxide — a trans-metallic material — into two layers of Ta2O5-x and TaO2-x and by controlling its surface.

A September 7, 2018 DGIST press release (also on EurekAlert), which originated the news item, delves further into the work,

The artificial synaptic device developed by the research team is an electrical synaptic device that simulates the function of synapses in the brain as the resistance of the tantalum oxide layer gradually increases or decreases depending on the strength of the electric signals. It has succeeded in overcoming durability limitations of current devices by allowing current control only on one layer of Ta2O5-x.

In addition, the research team successfully implemented an experiment that realized synapse plasticity [or synaptic plasticity], which is the process of creating, storing, and deleting memories, such as long-term strengthening of memory and long-term suppression of memory deleting by adjusting the strength of the synapse connection between neurons.

The non-volatile multiple-value data storage method applied by the research team has the technological advantage of having a small area of an artificial synaptic device system, reducing circuit connection complexity, and reducing power consumption by more than one-thousandth compared to data storage methods based on digital signals using 0 and 1 such as volatile CMOS (Complementary Metal Oxide Semiconductor).

The high-reliability artificial synaptic device developed by the research team can be used in ultra-low-power devices or circuits for processing massive amounts of big data due to its capability of low-power parallel arithmetic. It is expected to be applied to next-generation intelligent semiconductor device technologies such as development of artificial intelligence (AI) including machine learning and deep learning and brain-mimicking semiconductors.

Dr. Lee said, “This research secured the reliability of existing artificial synaptic devices and improved the areas pointed out as disadvantages. We expect to contribute to the development of AI based on the neuromorphic system that mimics the human brain by creating a circuit that imitates the function of neurons.”

Here’s a link to and a citation for the paper,

Reliable Multivalued Conductance States in TaOx Memristors through Oxygen Plasma-Assisted Electrode Deposition with in Situ-Biased Conductance State Transmission Electron Microscopy Analysis by Myoung-Jae Lee, Gyeong-Su Park, David H. Seo, Sung Min Kwon, Hyeon-Jun Lee, June-Seo Kim, MinKyung Jung, Chun-Yeol You, Hyangsook Lee, Hee-Goo Kim, Su-Been Pang, Sunae Seo, Hyunsang Hwang, and Sung Kyu Park. ACS Appl. Mater. Interfaces, 2018, 10 (35), pp 29757–29765 DOI: 10.1021/acsami.8b09046 Publication Date (Web): July 23, 2018

Copyright © 2018 American Chemical Society

This paper is open access.

You can find other memristor and neuromorphic computing stories here by using the search terms I’ve highlighted,  My latest (more or less) is an April 19, 2018 posting titled, New path to viable memristor/neuristor?

Finally, here’s an image from the Korean researchers that accompanied their work,

Caption: Representation of neurons and synapses in the human brain. The magnified synapse represents the portion mimicked using solid-state devices. Credit: Daegu Gyeongbuk Institute of Science and Technology(DGIST)

Nanotechnology-enabled acupuncture needles

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An Oct. 17, 2016 news item on phys.org makes an announcement about nanotechnology-enabled acupuncture needles (Note: The writing style is a little unusual for this kind of announcement),

A Daegu Gyeongbuk Institute of Science and Technology [Korea] research team led by Professor Su-Il In, who developed acupuncture needles combined with nanotechnology, was recognized as the world’s first application of this technology. This development is expected to open new directions in the oriental medicine research field.

Professor Su-Il In’s research team from the Department of Energy Systems Engineering succeeded in developing porous acupuncture needles (hereafter PANs) that offer enhanced therapeutic properties by applying nanotechnology on the acupuncture needles for the first time in the world.

The findings of this experiment, which was conducted in collaboration with DGIST’s research team and the Addiction Control Research Center at Daegu Haany University, have attracted the attention of the relevant academic field in light of the fact that the experiment combined nanotechnology with acupuncture needles.

An Oct. 17, 2016 DGIST press release on EurekAlert, which originated the news item, provides more technical detail,

Professor In’s research team developed PANs with fine pores ranging in sizes from nanometers (nm= one billionth of a meter) to micrometers (? = one millionth of a meter) on the surface of the needles using a nano-electrochemical method.

PANs are formed by anodization, and are characterized by a widened surface of the needles through the following process: anion (F-) contained in the electrolyte bored into the surface of the metal needles (positive) and created fine and uniform pores.

PANs are expected to be as effective as conventional large and long needles by minimizing the sense of pain during acupuncture treatment while expanding the surface area of the needle 20 times greater than conventional acupuncture ones.

Through electrophysiological experiments with rats, In’s research team proved that PANs excel in transferring signals from a spinal dorsal horn by the in vivo stimulation of Shenmen (HT7) points, and in particular, demonstrated that the efficacy of PANs is superior to conventional acupuncture needles in treating alcohol and cocaine addiction in animal experiments.

Applications for international patents for the fabrication technology of PANs developed by DGIST have already been submitted in countries such as the US, China, and Europe. In addition, in the domestic oriental medicine field, the fact that the efficacy of acupuncture needles has been improved through their structural transformation by applying nanotechnology has been recognized and evaluated as the first such instance in the thousand-year history of eastern medicine.

Professor Su-Il In from DGIST’s Department of Energy Systems Engineering said, “The development of nanotechnology has taken science and technology to the next level in various fields such as solar cells, quantum computers, display development, and the like. Based on this experiment’s achievement of combining nanotechnology and oriental medicine, I will continue to conduct research in order to be at the forefront of the scientific population of oriental medicine.”

Director Jae-ha Yang from Daegu Haany University said, “In western medicine, nanotechnology is widely used from diagnosis to treatment; but in eastern medicine, particularly in acupuncture therapy, it is rare to utilize nano science. The findings of this study are expected to open new directions in the field of eastern medicine where nano science is rarely explored and utilized.”

Here’s a link to and a citation for the paper,

Hierarchical Micro/Nano-Porous Acupuncture Needles Offering Enhanced Therapeutic Properties by Su-ll In, Young S. Gwak, Hye Rim Kim, Abdul Razzaq, Kyeong-Seok Lee, Hee Young Kim, SuChan Chang, Bong Hyo Lee, Craig A. Grimes, & Chae Ha Yang. Scientific Reports 6, Article number: 34061 (2016) doi:10.1038/srep34061 Published online: 07 October 2016

This paper is open access.