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New Carbon Nanotube Chip Outperforms Silicon Semiconductors (nanotechweb.org)
"Researchers at the University of Wisconsin-Madison are the first to have fabricated carbon nanotube transistors (CNTs) that outperform the current-density of conventional semiconductors like silicon and gallium arsenide," reports NanotechWeb.
Slashdot reader wasteoid
shares the site's interview with one of the researchers:
"When the transistors are turned on to the conductive state (meaning that current is able to pass through the CNT channel) the amount of current traveling through each CNT in the array approaches the fundamental quantum limit," he tells nanotechweb.org.
"Since the CNTs conduct in parallel, and the packing density and conductance per tube are very high, the overall current density is very high too -- at nearly twice that of silicon's. The result is that these CNT array FETs have a conductance that is seven times higher than any previous reported CNT array field-effect transistor."
The research was funded in part by the U.S. Army and Air Force, as well as the National Science Foundation. "The implication here is that by replacing silicon with a CNT channel, it should be possible for us to make either a higher performing device or one that works at lower power."
In other news, Fujitsu announced this week that it's joining an effort to release a 256-megabyte 55-nanometer carbon nanotube-based NRAM by 2018.
"Since the CNTs conduct in parallel, and the packing density and conductance per tube are very high, the overall current density is very high too -- at nearly twice that of silicon's. The result is that these CNT array FETs have a conductance that is seven times higher than any previous reported CNT array field-effect transistor."
The research was funded in part by the U.S. Army and Air Force, as well as the National Science Foundation. "The implication here is that by replacing silicon with a CNT channel, it should be possible for us to make either a higher performing device or one that works at lower power."
In other news, Fujitsu announced this week that it's joining an effort to release a 256-megabyte 55-nanometer carbon nanotube-based NRAM by 2018.
Hooray? There have been breathless articles about how diamond or CNT or whatever stomps silicon flat for 30 years now. The problem is that silicon is a moving target - it keeps being improved. If CNT or diamond is fundamentally better than the best possible silicon, which it probably is, the only way it can "catch up" is if silicon is improved to it's practical limits. That might be just a few years away - there's talk of the next few die shrinks being the last ones for silicon before physics don't allow any further improvement for 2d silicon wafers. (and 3d has the fundamental problem of trapping heat and much more difficult manufacturing)
Still, this is cool. I wonder if large scale power switch transistors can be a new future use for CNT tech? If they have better current flow and less "on" resistance, superior to silicon, that would be great.
Good. Maybe high-power motor controllers will become cheaper.
Don't stop where the ink does.
Sooner or later, somebody's going to look at this acronym and ask to buy a vowel.P>
I've calculated my velocity with such exquisite precision that I have no idea where I am.
We are close to peak compute as Moores law will be finished in a couple more shrinks. The next step will be in the software and the architecture and improvements will likely be linear not geometric as they have been since the invention of the integrated circuit. Fortunately it seems that the complexity of current computing systems is close to the number in biological brains so it may be enough. Carbon nanotubes may give one more generation of geometric shrink after the last silicon one but quantum physics - particularly the Heisenberg uncertainty principle mean that the route ends there. No doubt this will be taken advantage of over time but electronics will be largely done and dusted in about ten years. If I was a teenager looking for the most exciting career these days I would choose Genetics and not Electronics as the next bright future. I cannot wait for genetically modified humans to start winning the Olympics!
Facts are history now plebs have politics for religion on social media.
Have they found a practical way to mass produce single walled carbon nanotubes of arbitrary diameter and length yet?
I ask, because that is sadly a requirement for mass manufacture of quality ICs built using carbon semiconductor.
If they can pull that off cheaply and reliably, that enables carbon to really hit home as an industrial material, and things would get interesting.
Hand assembling an IC out of cherry picked parts in a cleanroom is not the same as the above. Yes, it lets you see that such chips have immense potential, but without a viable path to mass manufacture, the unit costs will be astoundingly prohibitive. Only the USA's DoD would be able to afford them. I really can't get behind such a nasty barrier in tech as that. The NSA has scary enough toys as is. Having access to ICs that they can drive many times harder than silicon, while the rest of us are left to pound sand due to the price, is not something I want to see.
100nm Transistors? It'll work for displays, but for logic those transistors are huge and as far as I can tell, they don't get smaller. The tubes are 1nm diameter and you need enough in parallel for it to work. At leasts that's what the low information article implied.
I should use this sig to advertise my book ISBN-13 : 978-1501515132.
Carbon is smaller than silicon.
At the moment the sensible money is on silicon. Make silicon circuits 10% smaller or 10% after and the whole of electronics benefits. If you try to do the same thing with carbon, then you have to re-invent many of the fabrication processes from scratch before you can make a single useful gadget.
In the long term, carbon is a no-brainer. It has a huge band gap will lets it be stable at high temperatures. It can bond to itself and be a super-resistor, a resistor, a semiconductor, and a conductor. Down the middle of carbon tubes it may even manage to be a superconductor. You could make a memory element using a few tens of atoms. Can you imagine having a mole of bits? On the other hand, trying to make a conductive track by doping silicon gets harder and harder as the size drops, and there are problems getting the current to turn corners in a single crystal.
So, what do we do in the middle-term? We can make something that is probably bigger than is ideal using the existing silicon technology. We will find a niche market that needs the same simple thing replicated lots of times - and non-volatile memory is the obvious choice - and leave making a carbon microprocessor for when we have more of the other bits working. That is what people have been predicting for years, and now they are actually beginning to do it.
Why are they dong it now? Well, I can remember over the past 40-odd years people saying you cannot get Si fabrication much below 10 microns, and then there were limits making them below 1 micron, and then you absolutely could no get below 0.1 micron. And as long as Silicon technology oprogressed, it was the better short-term investment. But as we go on, the next-generation silicon plants will be more expensive, the rewards are getting smaller, and the chances of some unexpected breakthrough dwindle. It is a good time for something to give.