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Flash alternatives graphene and memristor make progress

Scientists announce tests using atom-thick graphene and 5nm-thick memristors to provide media with many times the storage density of Nand flash and possible fuzzy logic computing

Stanford University scientists have published research following experiments with the one-atom-thick nanomaterial, graphene.

Three recent experiments at the US university have shown graphene to have 10 times more capacity than silicon-based memory, with a fraction of the footprint and power consumption.

Graphene was originally isolated a decade ago but, until now, has had relatively few practical applications. It is a purified relative of pencil lead and is formed when carbon atoms link together into sheets one-atom thick. Graphene is stronger than steel, as conductive as copper and has thermal properties useful in nanoscale electronics.

The graphene-based memory technologies work by applying jolts of electricity to the material to switch between conductive and non-conductive states.

Stanford professors HS Philip Wong and Eric Pop led an international group of collaborators who describe three graphene-centric memory technologies in separate articles in Nature Communications, Nano Letters and Applied Physics Letters.

“Graphene is the star of this research,” said Pop, a contributor to two of the three memory projects. “With these new storage technologies, it would be conceivable to design a smartphone that could store 10 times as much data, using less battery power, than the memory we use today.”

Wong said: “Data storage has become a significant, large-scale consumer of electricity, and new solid-state memory technologies such as these could also transform cloud computing.”

Memristor developments

Meanwhile, researchers at the Swiss National Science Foundation have demonstrated a Memristor based on material only 5nm thick and which can be switched between three state changes, providing a so-called trit to supersede the bit.

Read more about Nand flash alternatives

  • The recent announcement of 3D Xpoint memory by Intel and Micron poses questions about the future of storage and even the basic architecture of computing.
  • Flash storage has taken the enterprise by storm, but its days are numbered due to an unfavourable combination of technological obstacles and manufacturing economics. 

The ability to provide three stable resistive states opens the possibility of computing with a state between 0 and 1.

One of the researchers on the project, Jennifer Rupp, said: “This has interesting implications for what is referred to as fuzzy logic, which seeks to incorporate a form of uncertainty into the processing of digital information. You could describe it as less rigid computing.”

The principle of the memristor was first described in 1971 as the fourth basic component of electronic circuits alongside resistors, capacitors and inductors.

HP and Intel are both engaged in memristor research. 

This news comes hot on the heels of Micron and Intel’s announcement of 3D XPoint. It also offers 10 times the capacity density of Nand flash, but with a 1,000 times advantage in terms of speed and endurance. The companies involved claim products with 3D Xpoint will ship in 2016.

All three technologies are candidates to replace Nand flash over the next decade, a changeover which is driven by the need to overcome the difficulties of maintaining endurance and operational efficiency as flash shrinks to ever-smaller cell sizes.

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