New computer memory design improves performance and reduces energy demands

Researchers at the University of Cambridge have created a novel design for computer memory that can significantly boost performance while lowering the energy requirements of internet and communications technology.

These materials can behave similarly to synapses in the human brain, allowing information processing and memory to coexist in the same location.

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 allow electrons to pass through. 

This method of changing the electrical resistance in computer memory devices and allowing information processing and memory to coexist could lead to the development of computer memory devices with significantly higher density, higher performance, and reduced energy consumption.

The data-hungry world has increased energy needs, making it more 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 over the next ten years. 

First author Dr. Markus Hellenbrand, from Cambridge’s Department of Materials Science and Metallurgy, said, “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 energy and time.”

Resistive switching memory, which allows for a continuous range of states, is one potential solution to this challenge, leading to higher density and speed for computer memory devices.

Hellenbrand said, “A typical USB stick based on the continuous range would be able to hold between ten and 100 times more information, for example.” 

Hellenbrand and his colleagues created a prototype device out of hafnium oxide. This insulating material is already in use in the semiconductor industry. The uniformity problem arises when employing this material for resistive switching memory applications. When barium was added to thin films of hafnium oxide, strange structures perpendicular to the hafnium oxide plane began to appear.

These vertical barium-rich ‘bridges’ are highly organized and allow electrons to travel through, whereas the surrounding hafnium oxide is unstructured. 

An energy barrier was generated where these bridges meet the device contacts, which electrons can pass. The researchers adjusted the height of this barrier, which modified the electrical resistance of the composite material, allowing it to exist in many states.

The researcher said, “This allows multiple states to exist in the material, unlike conventional memory, which has only two states.” 

These hafnium oxide composites are self-assembled at low temperatures and exhibit excellent performance and homogeneity, making them ideal for next-generation memory applications. Cambridge Enterprise, the University’s commercialization arm, has filed a patent.

The researchers are collaborating with the industry to do larger feasibility tests on the materials to understand better how high-performance structures form.

The study was funded by the National Science Foundation of the United States and the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation (UKRI).

Journal Reference:

1. Hongyi Dou, Ming xiao, et al. Thin-film design of amorphous hafnium oxide nanocomposites enabling strong interfacial resistive switching uniformity.Science Advances.DOI: 10.1126/sciadv.adg1946