Tiny memory device shrinks even further in size

Engineers at The University of Texas at Austin (UT Austin) have created what they claim is the smallest memory device yet — and in the process realised the physics dynamic that unlocks the dense memory storage capabilities of these tiny devices.

The new device falls under the category of memristors, a popular area of memory research centred around electrical components with the ability to modify resistance between two terminals without a need for a third terminal in the middle known as the gate. That means they can be smaller than today’s memory devices and boast more storage capacity.

Two years ago, the UT Austin team created what was then the thinnest memory storage device ever recorded — dubbed an ‘atomristor’ — with a single atomic layer of thickness. But shrinking a memory device is not just about making it thinner, it’s also building it with a smaller cross-sectional area. Now the researchers have shrunk the cross-section area down to just a single square nanometre, publishing their breakthrough in the journal Nature Nanotechnology.

“The scientific Holy Grail for scaling is going down to a level where a single atom controls the memory function, and this is what we accomplished in the new study,” said UT Austin’s Professor Deji Akinwande. The new memristor also promises capacity of about 25 terabits per square centimetre — 100 times higher memory density per layer compared with commercially available flash memory devices.

Getting a handle on the physics that pack dense memory storage capability into these devices enabled the ability to make them much smaller. Defects, or holes in the material, provide the key to unlocking the high-density memory storage capability.

“When a single additional metal atom goes into that nanoscale hole and fills it, it confers some of its conductivity into the material, and this leads to a change or memory effect,” Prof Akinwande said. Though the researchers used molybdenum disulfide (MoS₂) as the primary nanomaterial in their study, they think the discovery could apply to hundreds of related atomically thin materials.

The race to make smaller chips and components is all about power and convenience. With smaller processors, you can make more compact computers and phones. But shrinking down chips also decreases their energy demands and increases capacity, which means faster, smarter devices that take less power to operate.

“The results obtained in this work pave the way for developing future generation applications that are of interest to the Department of Defense, such as ultradense storage, neuromorphic computing systems, radiofrequency communication systems and more,” said Pani Varanasi, Program Manager for the US Army Research Office, which funded the research.

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