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IBM Hardware Technology

Graphene Transistors 10x Faster Than Silicon 170

Posted by kdawson
from the can't-be-too-rich-either dept.
Asadullah Ahmad writes "IBM has created transistors made from carbon atoms, which operate at 100 gigahertz, while using a manufacturing process that is compatible with current semiconductor fabrication. With silicon close to its physical limits, graphene seems like a viable replacement until quantum computing gets to desktop. Quoting: 'Researchers have previously made graphene transistors using laborious mechanical methods, for example by flaking off sheets of graphene from graphite; the fastest transistors made this way have reached speeds of up to 26 gigahertz. Transistors made using similar methods have not equaled these speeds.'" The other day we discussed what sounds like similar research by a group of scientists at Tohoku University; that team did not produce transistors, however.
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Graphene Transistors 10x Faster Than Silicon

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  • by eldavojohn (898314) * <eldavojohn.gmail@com> on Friday February 05, 2010 @11:20AM (#31034718) Journal

    The other day we discussed what sounds like similar research [slashdot.org] by a group of scientists at Tohoku University; that team did not produce transistors, however.

    Surely that is some sort of joke. From the summary of the Tokyo University article:

    A new paper entitled Epitaxial Graphene on Silicon toward Graphene-Silicon Fusion Electronics published by a group of physicists at Tohoku University in Japan has demonstrated that they can grow graphene on a silicon substrate and pair that technique with conventional lithography to create a graphene-on-silicon field effect transistor.

    Not to mention that article is a myriad of highly moderated comments admonishing the staleness of graphene on silicon transistors.

    • by ls671 (1122017) *

      > Surely that is some sort of joke.

      Too bad if it is, we have been waiting for this for a while now since silicon based chips kind of reached their frequency limits. Of course, there is quantum computing but it is not coming to your local store soon ;-))

      It would be nice to be able to fit a 100 gigahertz chip in current hardware architectures...

    • Re: (Score:2, Informative)

      The other day we discussed what sounds like similar research [slashdot.org] by a group of scientists at Tohoku University; that team did not produce transistors, however.

      Surely that is some sort of joke. From the summary of the Tokyo University article:

      A new paper entitled Epitaxial Graphene on Silicon toward Graphene-Silicon Fusion Electronics published by a group of physicists at Tohoku University in Japan has demonstrated that they can grow graphene on a silicon substrate and pair that technique with conventional lithography to create a graphene-on-silicon field effect transistor.

      Not to mention that article is a myriad of highly moderated comments admonishing the staleness of graphene on silicon transistors.

      From reading what you quoted, it's not certain that Tohoku produced anything, at least not a graphene transistor. They did however demonstrate that they can grow graphene on a silicon substrate, and that they can pair that technique with conventional lithography to create a graphene-on-silicon field effect transistor. It's just not clear that they did create a graphene transistor, or at least anything comparable to what IBM apparently is producing.

    • Re: (Score:3, Informative)

      by VitaminB52 (550802)
      Maybe you would like to read http://en.wikipedia.org/wiki/FET [wikipedia.org]
      • So are we going back to saying 'FET's from almost everything 'MOSFET's? I'm assuming that the 'metal oxide semiconductor' will no longer be applicable when using graphene (at least from that I understand of how the graphene transistors are comprised of). We'll have to replace a bunch of acronyms, like NMOS and PMOS. What'll be the new name? G-MOS?
  • by LikwidCirkel (1542097) on Friday February 05, 2010 @11:27AM (#31034764)
    With all the stories of highly-experimental new, novel types of transistors - the majority of which are expensive-research only with no chance of commercialization any time soon, it's refreshing to see something that actually takes production feasibility into account.
  • by Thanshin (1188877) on Friday February 05, 2010 @11:28AM (#31034776)

    Year 2173:

    "Hidrogen-Unobtanium polycomposites seems like a viable replacement until quantum computing gets to desktop."

  • by Cytotoxic (245301) on Friday February 05, 2010 @11:30AM (#31034808)
    IBM research is typically the traditional 10 years away - but not this one... from TFA:

    "This is not pie-in-the-sky stuff, this is real," he says. "This development is really going to turn into a communications device not too long from now."

    So, I won't be playing Crysis on this transistor next month, but I might be using it to make a phone call "not too long from now".

    • by chrysrobyn (106763) on Friday February 05, 2010 @01:36PM (#31036538)

      IBM research is typically the traditional 10 years away - but not this one

      My VLSI professor was in the forefront of the industry. He had some very good contract with some good R&D firms. One day, he told us that copper might one day replace aluminum as wires in chips. The lower resistance would make a big difference, but nobody had overcome the increased reactance yet. The next day, IBM announced that they had figured it all out. A year later, copper interconnect was being used in chips, and 6 months later, in iBooks. The same professor in a subsequent class was discussing SOI with similar promises of improvements, and similar "nobody has it figured out yet". A few weeks later, IBM came through again with an announcement. 2 years later, there it was in products.

      With game changers like SOI and copper, IBM has gone to market in much less than 5 years.

      As a former circuit designer, and still a CPU engineer, I can say without hesitation that I don't care about graphene. The transistors aren't the big factor anymore. Sure, smaller transistors are good to increase transistors per die, and reduce the distance between them, but wire RC delay is the big deal. Even if the Ioff goes down and Ion goes up, the speed of the chip isn't going to change much.

      Things aren't going to get much better than copper -- it's very good already. Even if they upgraded to slightly lower resistance silver (and talk about a reactive metal!), the delay wouldn't change much. Lower K dielectric would help too. There are some minor improvements that can be done, but we're probably talking 5% here and there, and they probably don't add up to 20%.

      Architecture changes are going to be important, from instruction optimization to multiple cores. The automated synthesis tools available also have an amazing amount of potential improvement -- placement and routing is a field with a lot of graph theory headroom. There is a world of difference still between "good enough" synthesis and what can be done by a well trained technician.

      • Another chip designer here ...

        Anything that lets us make transistors faster without paying a huge cost in leakage (power consumption when not switching) is a win. It sucks to go from one process node to the next and get almost no performance benefit unless you're willing to pay a leakage penalty. SOI rocks, but not everybody has it. Therefore, I'm a bit more excited about graphene than you are.

      • by imgod2u (812837)

        As a former circuit designer, and still a CPU engineer, I can say without hesitation that I don't care about graphene. The transistors aren't the big factor anymore. Sure, smaller transistors are good to increase transistors per die, and reduce the distance between them, but wire RC delay is the big deal. Even if the Ioff goes down and Ion goes up, the speed of the chip isn't going to change much.

        Sure it does. Current circuit speed is still (despite predictions) dominated by capacitance. This includes both load capacitance on the transistors themselves (which, mind you, is still not trivial compared to interconnect) and load capacitance on the metal itself.

        To decrease rise and fall time you can either decrease capacitance (shorter wires) or increase the drive current, which faster transistors do.

        And while transistor frequency scaling isn't overwhelmingly dominant as they were back in 0.35um, they st

  • 3D chips (Score:5, Interesting)

    by BlueParrot (965239) on Friday February 05, 2010 @11:33AM (#31034844)

    To be honest I'm more interested in seeing proper 3D chips become reality. If you find some affordable way to produce chips with, say 10 000 layers, then processing power per volume unit would increase rapidly.

    I think the major obstacle is going to be what to do about heat. The center of such a chip-stack would probably get quite hot so you probably want to run some form of liquid cooling through the chip itself. Alternatively materials like silicon carbide or diamond might be able to cope better with the high power density.

    • The center of such a chip-stack would probably get quite hot so you probably want to run some form of liquid cooling through the chip itself.

      Once you're creating enough layers, there's nothing preventing the designers to create a 3D structure that's similar to that of a heatsink. Basically, it'll be designed with more surface area so that it can be cooled effectively. Probably a batch of fin-like elements that are connected together. And you wouldn't have to run liquid through it -- just fill the spaces between the semiconductor material with a better heat-transferring material (like copper, or eventually artificial diamond), and have that conne

      • by khallow (566160)
        You remain limited by heat flow through the boundary of the chip package (which isn't improved by making it a fractal shape). As some point you will need a transport fluid to get heat transfer past the limits of conductive and radiative cooling.
        • Yes, but this is like walking before running. Pumping water with miniature compressors within a semiconductor would mean a complex mechanical system which would be difficult to scale (in production, I mean). While the convex hull remains the same, you can still increase the surface area, which will help with heat transport if the material that envelopes it is a better heat conductor than the semiconductor material.
    • by ianare (1132971)

      Quite right. [usatoday.com]

    • Re: (Score:3, Interesting)

      by damburger (981828)

      3D chip manufacturing would be interesting. As well as having a possible stepping stone towards universal fabrication, you would also have a great increase in the potential number of connections between processing elements. Connectivity is one of the main divides between silicon and neural tissue, so this may have implications for artificial intelligence. Two singularities for the price of one!

      • by hlee (518174)

        3D chips will not take us any closer to true AI.

        We still don't truly understand the nature of intelligence, and we won't be able to manufacture it unless we can define it formally in some mathematical/logical notation.

        I've done some work with neural networks, and we can simulate neurons with any number of connections (inputs and outputs), but having a bunch of neurons work together discerning things is not intelligence.

    • I think that a kind of fractal volume for the CPU (which will maximize the surface between the cooling fluid and the heating parts of the CPU) could be pretty cool (no pun intended!), but quite hard to manufacture.

    • Heat is caused by power dissipation. Not only has IBM been researching how to integrate cooling channels inside of chips, they've also been researching ways to create circuits that recycle as many of the electrons as possible, to avoid dissipating heat. Hopefully they'll work something out that will enable 3D chips. The connectivity possibilities are intriguing.

      IBM still does do basic research, and they seem to believe in liberal licensing, judging by the 2 terabyte hard drives that can be had. Hopefull

    • Although 3D chips would be advantageous, they would not be as big a gain as it first appears. With devices and conductive layers, the electrically used portion of modern ICs is about 30 times as deep as the minimum feature size. (I've been out of the field for a decade, corrections appreciated.) That includes a few layers for the active devices and maybe 6 layers for conductors. So for a 20 nanometer process, 10,000 layers of which 1,000 are active device layers, the first nominal expectation is 1,000 times
    • by imgod2u (812837)

      The problem is that processing power doesn't scale linearly with number of transistors you can fit in an area. That's the primary concern over the frequency scaling of silicon. You can cram more transistors in some space but if they can't run faster, your options are: 1. more cache 2. dual core 3. more specialized functions.

      None of these will universally speed up computing like frequency scaling will.

  • by marciot (598356) on Friday February 05, 2010 @11:39AM (#31034916)

    It was bad enough when computers were made out of mere sand, now they will be made out of coal?

    Can't they make computers out of sapphires or something so I can feel sophisticated when I buy it?

  • by Anonymous Coward on Friday February 05, 2010 @11:40AM (#31034924)

    "The prototype devices, made from atom-thick sheets of carbon, operate at 100 gigahertz"

    Define operate? This sounds like the cut-off frequency, which is 100s of GHz for Si CMOS. How is 200GHz 100GHz? And no, this does not mean it can switch this fast. If it can switch this fast, it would likely operate into the THz, and we would be interested in using it for THz applications. Maybe operate is maximum stable oscillation frequency? Ft? Fmax? It's sure as hell not a switching frequency, despite what the article tells us.

    "Growing transistors on a wafer not only leads to better performance, it's also more commercially feasible"

    Growing transistors on a wafer? As compared to what? A waffle?

    Done reading... moving on...

  • Imagine at what speed the cards are going to come down and bounce in the "Solitaire" Windows game at 100 Ghz!
  • graphene provides a promising potential replacement because electrons move through the material much faster than they do through silicon

    Could someone elaborate on that statement? I assume that they mean that an electron will move through the material with "less interference", like light traveling through space will be "faster" (to reach its destination) than if it were traveling through matter. Is that what they mean?

    • In addition to fewer scattering events, I believe the energy required to affect the electron bonds on graphene is less than on silicon, so you reach the energy level faster, so you move the electron along faster.

    • by imgod2u (812837)

      Graphene in its conductive state has a much lower resistance/area than silicon semiconductors. There's also far less scattering.

      This means more electrons can move through a piece of graphene than a piece of silicon of the same size per second.

  • Interconnects (Score:4, Interesting)

    by John Hasler (414242) on Friday February 05, 2010 @11:49AM (#31035006) Homepage

    Graphene will probably be at least as important as a replacement for metallic interconnects as for transistors. Much of the area of a chip is covered by interconnects they are responsible for much of the heat and delay.

  • by kiehlster (844523) on Friday February 05, 2010 @11:50AM (#31035020) Homepage
    I have my doubts on whether we'll ever see this because of two things from the article: "first applications of graphene transistors will likely be as switches and amplifiers in analog military electronics" and "Graphene's properties are very sensitive to its environment". This means IBM is placing dainty technology into the hands of the harsh military environment. I've heard how rigorously they test military electronics, and if Graphene is sensitive enough to require insulation, then it's never going to make it past those extreme environment tests they do. Has anyone else seen sensitive materials make it through military applications?
    • by derGoldstein (1494129) on Friday February 05, 2010 @12:04PM (#31035196) Homepage
      You're assuming that the transistors themselves will have to go into a hostile environment. Some of them do, but when you're talking about HPC then they'll probably be in a remote location, safe and protected (like Cheyenne Mountain, maybe near the Stargate...).
    • Re: (Score:2, Informative)

      by Anonymous Coward

      They mean the gate dielectric (which is used for the majority of transistor designs, silicon or otherwise) not that the transistors need insulation from the environment - graphene is more sensitive to the dielectric material (ie the enivronment around the transitior) than silicon. Extreme external (ie military) environment is irrelevant as the entire chip is packaged up anyway.

    • Look up "hermetic seal" in Wikipedia.

    • Oh yes, I worked on some pretty dainty equipment in the Army,the abbreviated Guided Missile test set for the Hawk Missile [wikipedia.org], just starting the truck meant 8 hours of work getting the equipment back into alignment.

  • I wonder what a fuzz box made of these would sound like...

    • by Lisandro (799651)

      Hear hear!

      For those interested: basic guitar fuzzboxes (like the venerable Fuzz Face [ning.com]) are simple, design arround one or two transistors. The sound is heavily dependent on the type transistor used - old Germanium devices have a nicer, more musical sound than modern Silicon ones; this depends on how they clip the signal when amplifying, basically. I'd love to hear one using these new devices...

  • by noidentity (188756) on Friday February 05, 2010 @11:59AM (#31035140)

    The prototype devices [...] can switch on and off [...] about 10 times as fast as the speediest silicon transistors.

    These transistors are only about 9x faster than silicon, not 10x faster as the Slashdot headline claims.

  • hold yer horses (Score:5, Informative)

    by lurgyman (587233) on Friday February 05, 2010 @12:19PM (#31035380)
    Before you get yourselves worked up, realize there is no mention in this article or the original article in "Science" for applying this for computing. There's somewhat of a misstatement in the technology review article - if you look at the actual article in Science (http://www.sciencemag.org/cgi/content/abstract/327/5966/662), the 100GHz figure is the unity (or cutoff) gain frequency (e.g., how high of a frequency you can build an amplifier) and not switching. There is no mention of switching in the paper by the IBM scientists, and that is the application relevant to computing. Even TFA's expert is talking about using this in analog communication frontends, folks. Sorry.
    • if the channel can pinch *almost* open/shut at 100Ghz, then the transistor can switch a lot faster than silicon, too.

  • graphene seems like a viable replacement until quantum computing gets to desktop
     
    With everyone quitting smoking, we've run out of dead people's lungs to scrape carbon out of, so we've reached the limits of carbon-based CPUs and had to switch to graphene.
     
    But the extra pencils from companies going paperless will only last so long. When we run out, we will have to switch to making quantum CPUs. Hopefully by then, making quantums will be a lot cheaper.

  • All right! Now we have a chip that we can get rid of using an eraser!

  • The summary doesn't mention it, but is the integration scale potentially competitive? I'd assume so, since it's supposed to be commercially viable, but of course I didn't RTFA.

  • The future of computing is gallium arsenide^h^h^h^h^h^h^h^h^h^h^h^h^h^h^h^hphotonics^h^h^h^h^h^h^h^h^hmolecular switches^h^h^h^h^h^h^h^h^h^h^h^h^h^h^h^h^h^hquantum whatnot^h^h^h^h^h^h^h^h^h^h^h^h^h^h^hummmmmmm^h^h^h^h^h^h^h^hgraphene?^h!

  • by MattskEE (925706) on Friday February 05, 2010 @06:36PM (#31040528)

    Graphene is still very much a lab technology which isn't anywhere near ready for commercial production of devices. It may turn out to replace Silicon one day, but guess what, people keep doing amazing shit with silicon because it's still the cheapest material system for fabrication.

    Apologies to those without IEEE access, but here is a paper discussing a recent 150GHz Silicon CMOS amplifier: A 1.1V 150GHz amplifier with 8dB gain and +6dBm saturated output power in standard digital 65nm CMOS using dummy-prefilled microstrip lines [ieee.org]. That's pretty awesome in my book. It's pushing the amplifier very close to fmax of the actual transistors, but it works and it's in a commercial silicon process.

    There are always applications where we can do better systems with more expensive materials like GaAs, GaN, InP, Graphene, etc... but silicon is cheap and easily mass-produced, so lots of engineers work on pushing it to incredible performance.

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