IBM proves there is life after silicon

It’s a widely held belief that conventional silicon based circuitry will become unviable once manufacturing processes reach 7 nanometres.

Further than this, current silicon chips would be unable to function and the threshold is slowly approaching as chip designs edge closer to single digit processes.

This means that, in order to progress in line with Moore’s Law, someone’s got to find new ways to develop chips.  

IBM has been one of the firms at the forefront of developing one of the brightest hopes for the future chip, graphene.  Now, Big Blue has announced a series of prototype chips based on some of the most promising alternative designs.

A the IEEE International Electron Devices Meeting, IBM boffins lifted the lid on some of their attempts to produce a new breed of chips, which crucially are compatible with current CMOS production technology on 200mm wafers.

IBM scientists have, for the first time they claim, managed to create a graphene device that is CMOS compatible and able to function at up to 5 GHz while keeping stable at even 200 degrees. 

The design is a change to current attempts at graphene transistor structures.  According to the team, this involves developing an embedded gate structure that “enables high device yield on a 200mm wafer”, rather than trying to deposit gate dielectric on an inert graphene surface.

Another technology which IBM thinks could revolutionise chip engineering is Racetrack memory.  This combines the attributes of magnetic hard drives and solid state memory. The company has a prototype which exhibited both read and write functionality of “256 in-plane, magnetized horizontal racetracks”, which we’re sure is quite good.

If scientists are able to make the technology more reliable, after seven of years of development so far, then it could lead to a new form of computing which would allow masses of data to be accessed in a billionth of a second, the company claims.

Carbon nanotubes are often talked about as a future technology, and IBM researchers have developed what they claim is the first transistor with sub-10nm channel lengths.  According to IBM it’s “outperforming the best competing silicon-based devices at these length scales”.

Outside of Big Blue’s labs, another announcement today showed that there is indeed life after silicon.

Advances in the use of molybdenite-based chips at the Laboratory of Nanoscale Electronics and Structures (LANES) in Switzerland have given silicon a run for its money. 

The lab began looking at molybdenum disulfide (MoS2) earlier this year, and reckon that it offers advantages over silicon in terms of minituarisation, electricity consumption and mechanical flexibility.   In fact, they even think it’s better in some ways than attention-hogging graphene.

LANES says the material is a relatively abundant, naturally occurring mineral, and its semiconducting properties make it a bit nifty for using in transistors.

The main reason boffins are so excited about it is that it allows for reducing transistor size, enabling further miniaturisation – the holy grail for chip development.

It’s possible, claim the scientists, to construct layers of molybdenite that are just three atoms thicks, which the researchers say is at least three times smaller than feasible with silicon. Even at this point Molybdenite can conduct and should remain stable.

The chips could possibly be used in flexible electronics, one of the first applications that expected for graphene.

Which of the alternative materials could take the crown, if at all, is unclear – there’s still a long way to go before silicon reaches a dead end.