IBM Scientists Find New Way To Shrink Transistors

MarcAuslander writes that IBM scientists have discovered a way to replace silicon semiconductors with carbon nanotube transistors, an innovation the company hopes will dramatically improve chip performance and get the industry past the limits of Moore's law. According to the Times: In the semiconductor business, it is called the 'red brick wall' — the limit of the industry's ability to shrink transistors beyond a certain size. On Thursday, however, IBM scientists reported that they now believe they see a path around the wall. Writing in the journal Science, a team at the company's Thomas J. Watson Research Center said it has found a new way to make transistors from parallel rows of carbon nanotubes.

Comments

Limits of Moor's law??

[trollingaround]

The Moore law that I know says that the number of transistor in a IC, double approximately every two years. Is there another one that specifies some limits?

Re: Limits of Moor's law??

[Anonymous Coward]

It's the Law. Why do you question it?

Oh, because you can think critically.

The next person that quotes Moore's Law to me like it's anything other than an observation of one man that happened to be true for a decent period of time is getting a Lawgiver to the face.

Re:Limits of Moor's law??

[GrahamCox]

It's a badly and lazily written summary. Moore's "law" doesn't specify any limits, but for a while Moore's law hasn't held true because of some unforeseen physical limits of the current silicon technology we use.

This new technology may or may not deliver what it promises, but if it does, it will be a resumption of Moore's law, not breaking it. If anything, Moore's "law" was broken several years ago by the existing technology not living up to it.

I put "law" in quotes because it's not actually a law, just a prediction, and a rather wishful one at that.

Re:Limits of Moor's law??

[Anonymous Coward]

There is a good reason why that buys you nothing, and costs you much: Basically, the thermal dissipation of a device of a given geometry is what gives it state, by thermalising the state change, it prevents quantum annealing from returning it to the previous or indeterminate state. To increase the number of states you have to increase the voltage proportionally to the number of states, so to add one extra bit (remember a bit is just log2(possible states)), you have to double the number of states, and therefore the voltage; all well and good? No, because the dissipation of a device is proportional to the square of voltage, so you have doubled the bit density by quadrupling the energy consumption of the device.

And this is not even taking into account the added complexity (more gates) required to at some point discriminate these levels to implement logic. This also roughly scales to the square of the number of states. So you take the square of the square of the number of states, or raise the activation energy to the fourth power of what it was, at least making the device 8x more energy dense or less efficient for a 2x gain (this is the hard limit of information theory, real numbers are worse).

Now there of course is still room at the bottom to make these quantum annealing devices we call switches more efficient, but the way you are proposing is working in the opposite direction.

If you want a computer to be reliable, that is compute things much more often than uncompute things, you have to have a thermal bias, so that P(compute) >> P(uncompute), which we do by setting up an entropy gradient and periodically saving the result of some combinatorial equation to a register where it's value is constantly reinforced by that entropy gradient (current flowing through the latch), or else held in that state by lifting it over an activation barrier (as in memristors and Flash). Either way energy is consumed in the process, as you lift it into a indeterminate state and allow it to relax into the desired determinable state. The clock and Vdd provide together provide this energy to allow this to function.

-puddingpimp

Show Me Something Made with C Nanotubes!

[Irate Engineer]

I've seen tons of articles like this over the last decade, touting carbon nanotubes as being the enabling technology for all sorts of improved applications.

Can anyone actually point me to something that has made it to production utilizing carbon nanotubes? I'm not being snarky here - I'm really curious to know if any of this is actually getting off the workbench into mainstream use anywhere.

Carbon nanotubes hit me as being a wonder invention like nuclear fusion; if we can build it it will be awesome, but we probably won't be able to build it for at least $DATE + 20 years.