The new technology can fit 10 to 100 times more information on one device and process it in one place. The new memory processes data in a similar way as synapses in the human brain. A feature of the memory is resistance switching, which is capable of a continuous range of states, unlike traditional memory, which has only two states: one or zero.
Prototype device based on hafnium oxide, a material already used in the semiconductor industry. The technology was patented by the Cambridge Business Enterprise.
One potential solution to the problem of inefficient computer memory is a new type of technology known as resistive switching memory. Conventional memory devices are capable of two states: one or zero. A functioning resistive switching memory device however, would be capable of a continuous range of states – computer memory devices based on this principle would be capable of far greater density and speed.
“A typical USB stick based on continuous range would be able to hold between ten and 100 times more information, for example,” said Hellenbrand.
Hellenbrand and his colleagues developed a prototype device based on hafnium oxide, an insulating material that is already used in the semiconductor industry. The issue with using this material for resistive switching memory applications is known as the uniformity problem. At the atomic level, hafnium oxide has no structure, with the hafnium and oxygen atoms randomly mixed, making it challenging to use for memory applications.
However, the researchers found that by adding barium to thin films of hafnium oxide, some unusual structures started to form, perpendicular to the hafnium oxide plane, in the composite material.
These vertical barium-rich ‘bridges’ are highly structured, and allow electrons to pass through, while the surrounding hafnium oxide remains unstructured. At the point where these bridges meet the device contacts, an energy barrier was created, which electrons can cross. The researchers were able to control the height of this barrier, which in turn changes the electrical resistance of the composite material.
“This allows multiple states to exist in the material, unlike conventional memory which has only two states,” said Hellenbrand.
Unlike other composite materials, which require expensive high-temperature manufacturing methods, these hafnium oxide composites self-assemble at low temperatures. The composite material showed high levels of performance and uniformity, making them highly promising for next-generation memory applications.
A patent on the technology has been filed by Cambridge Enterprise, the University’s commercialisation arm.
“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,” said Hellenbrand.
The researchers are now working with industry to carry out larger feasibility studies on the materials, in order to understand more clearly how the high-performance structures form. Since hafnium oxide is a material already used in the semiconductor industry, the researchers say it would not be difficult to integrate into existing manufacturing processes.
The research was supported in part by the U.S. National Science Foundation and the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation (UKRI).