Boffins prep tasty data-cramming 3D metal-sandwich chip

Boffins have constructed a microprocessor architecture capable of packing in up to 1,000 times more data than today’s generation of processors.

Crucially, the data in the chips is recorded and stored using the spin of electrons.

Physicists at the University of Cambridge have built a 3D microchip that crams data into a three-layered sandwich of horizontally stacked metals. It’s called 3D because data can move up and down between the layers – instead of just traveling left and right across the processor, as in conventional chips.

Professor Russell Cowburn, lead researcher on the project from the Cavendish Laboratory at the University of Cambridge, told The Reg: “This is the first time spintronics has been done in three dimensions.”

The breakthrough is that the team has devised a practical and potentially cost-effective way of making the layering work: the physicists use a "magnetic ratchet" that allows information to be unidirectionally shifted from one magnetic layer to another.

It’s the layering in the 3D chip that increases the amount of available memory – between 10 and 1,000 times as much as previously possible, Cavendish estimates. But it’s difficult and costly to move data up and down through the layers.

In a stacked architecture you need so many transistors that the cost becomes prohibitive as does the power needed to make the gates work. Transistors also add bottlenecks, potentially slowing the chip’s performance.

The 3D microchip has been built using cobalt, platinum and ruthenium atoms layered one on top the other. Their magnetic properties and reaction to each other controls the electron spin.

The approach means data can be successfully written and stored in the layers expanding its capacity without expanding the chip’s horizontal footprint and also adding more transistors as interconnects.

Spintronics is already used in MDRAM memory chips from companies such as Everspin Technologies: Dell uses Everspin for RAID-on-a-chip in its PowerEdge servers and PowerVault storage system, and LSI on its RAID controller cards. Everspin is also used in appliances, cars and aerospace.

However, MDRAM is two-dimensional and the hope is that spintronics can go 3D in mainstream memories. Cowburn warns, though, that more research is needed as this is currently at the stage of applied physics. At the moment, the team’s moving just two data bits through 11 shift registers. ®