Scientists have created a novel framework for computer memory that could boost performance while lowering the energy requirements of internet and communications technologies, which are expected to consume about a third of global electricity in the next 10 years.
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The University of Cambridge-led team developed a device that processes data in the same manner that synapses in the human brain do. The devices are made of hafnium oxide, a material already used in the semiconductor industry, and small self-assembled barriers that can be raised and lowered to permit electrons to pass through.
This approach of altering the electrical resistance in computer memory devices and enabling information processing and memory to coexist could contribute to developing computer memory devices with significantly higher density, higher performance, and reduced energy consumption. The findings were published in the journal Science Advances.
The data-hungry world has resulted in an increase in energy needs, making it increasingly difficult to cut carbon emissions. Artificial intelligence, internet usage, algorithms, and other data-driven technologies are predicted to consume more than 30% of global electricity in the coming years.
To a large extent, this explosion in energy demands is due to shortcomings of current computer memory technologies. In conventional computing, there’s memory on one side and processing on the other, and data is shuffled back between the two, which takes both energy and time.
Dr. Markus Hellenbrand, Study First Author, Department of Materials Science and Metallurgy, University of Cambridge
A new form of technology called resistive switching memory is one potential answer to the problem of ineffective computer memory. Traditional memory devices have two states: one or zero. A working resistive switching memory device, on the other hand, would be capable of a continuous variety of states—computer memory devices based on this approach would be significantly denser and faster.
A typical USB stick based on continuous range would be able to hold between ten and 100 times more information, for example.
Dr. Markus Hellenbrand, Study First Author, Department of Materials Science and Metallurgy, University of Cambridge
Hellenbrand and his coworkers created a prototype device out of hafnium oxide, an insulating material commonly used in the semiconductor industry. The uniformity problem arises when employing this material for resistive switching memory applications. Hafnium oxide has no structure at the atomic level, with hafnium and oxygen atoms randomly combined, making it difficult to employ for memory applications.
However, the researchers discovered that by adding barium to thin layers of hafnium oxide, some unexpected structures started to surface in the composite material, perpendicular to the hafnium oxide plane.
These highly structured vertical barium-rich “bridges” permit electrons to travel through while the surrounding hafnium oxide stays unstructured. An energy barrier was generated where these bridges meet the device contacts, which electrons can pass. The scientists were able to control the height of this barrier, altering the electrical resistance of the composite material.
“This allows multiple states to exist in the material, unlike conventional memory which has only two states,” notes Hellenbrand.
These hafnium oxide composites self-assemble at low temperatures, unlike other composite materials that require expensive high-temperature manufacturing processes. The composite material demonstrated excellent performance and uniformity, making it ideal for next-generation memory applications.
Cambridge Enterprise, the University’s commercialization arm, has filed a patent on the technology.
What’s really exciting about these materials is they can work like a synapse in the brain: they can store and process information in the same place, like our brains can, making them highly promising for the rapidly growing AI and machine learning fields.
Dr. Markus Hellenbrand, Study First Author, Department of Materials Science and Metallurgy, University of Cambridge
The researchers are currently collaborating with the industry to do broader feasibility investigations on the materials to truly comprehend how high-performance structures form. Because hafnium oxide is currently used in the semiconductor industry, scientists believe it would be simple to incorporate into existing manufacturing processes.
The study was funded in part by the National Science Foundation of the United States and the Engineering and Physical Sciences Research Council (EPSRC), which is part of UK Research and Innovation (UKRI).
Journal Reference:
Hellenbrand, M., et al. (2023). Thin-film design of amorphous hafnium oxide nanocomposites enabling strong interfacial resistive switching uniformity. Science Advances. doi.org/10.1126/sciadv.adg1946.