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Space Hardware Science

Can New Metal-Air Transistors Replace Semiconductors and Continue Moore's Law? (ieee.org) 153

Posted by EditorDavid from the s'mores-law dept.
Will Moore's law really come to an end by 2025? Maybe not...

An anonymous reader quotes IEEE Spectrum: [R]esearchers at RMIT University in Melbourne, Australia, believe a metal-based field emission air channel transistor (ACT) they have developed could maintain transistor doubling for another two decades. The ACT device eliminates the need for semiconductors. Instead, it uses two in-plane symmetric metal electrodes (source and drain) separated by an air gap of less than 35 nanometers, and a bottom metal gate to tune the field emission. The nanoscale air gap is less than the mean-free path of electrons in air, hence electrons can travel through air under room temperature without scattering...

Using metal and air in place of semiconductors for the main components of the transistor has a number of other advantages, says Shruti Nirantar, a Ph.D. candidate in RMIT's Functional Materials and Microsystems Research Group. Fabrication becomes essentially a single-step process of laying down the emitter and collector and defining the air gap. And though standard silicon fabrication processes are employed in producing ACTs, the number of processing steps are far fewer, given that doping, thermal processing, oxidation, and silicide formation are unnecessary. Consequently, production costs should be cut significantly. In addition, replacing silicon with metal means these ACT devices can be fabricated on any dielectric surface, provided the underlying substrate allows effective modulation of emission current from source to drain with a bottom-gate field. "Devices can be built on ultrathin glass, plastics, and elastomers," says Nirantar. "So they could be used in flexible and wearable technologies."
The article also suggests ACT devices could become important in space exploration, since electrons would be unaffected by extraterrestrial vacuums and radiation.

Nirantar was lead author on a new paper published in Nano Letters, and believes that their new approach "means we can stop pursuing miniaturization, and instead focus on compact 3D architecture, allowing more transistors per unit volume."
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Can New Metal-Air Transistors Replace Semiconductors and Continue Moore's Law? More

Can New Metal-Air Transistors Replace Semiconductors and Continue Moore's Law?

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  • Besides home and professional appliances are fast and small enough today, even scientific appliances are "good enough" today...
    • The only matter, I think, is it's cost...

      • Re:Moore's Law is irrelevant now (Score:4, Interesting)

        by Darinbob ( 1142669 ) on Sunday December 02, 2018 @12:24PM (#57736778)

        Power consumption too! It's a major factor in a lot of designs today. This means fewer batteries, and less recharging or replacement. I'm working on stuff that needs a 20 year life out of a single small battery, and some that need to survive off of a capacitor for a few minutes after a power outage. The consumer oriented model of recharging nightly or constantly buying new batteries deserves to become a thing of the past.

        • The consumer oriented model of recharging nightly or constantly buying new batteries deserves to become a thing of the past.

          Moore's Law will never fix that, as it's a design problem, not a technical one. Like with storage space, every time a better device comes out, designers find new and improved ways of completely wasting whatever resources are available. Also, managers have a say in the design process, which is why most batteries these days aren't easily replaceable.

          I'm all for pushing Moore's Law along, but being the cynical old bastard I am, I'm sick of new devices being such a pain in the ass because of the idiotic and i

    • That explains why home consumers want the same quality stuff they think professionals are getting.
      • Home user already have professional-grade appliances now (they just don't know how to use it)
        • I'm not talking more about what a group of home users thinks is going on in the news and then decides they should have something too. That is completely different from a home user who happens to have a device they use differently from a professional. Kind of like wanting a yacht because other people have one versus having a sailboat but never using the sails.
      • "professional grade" usually means "not as many fancy stuff, but can take a beating". Despite what they think, most consumers don't want "pro-stuff"--they prefer the bells & whistles.

        • Professional may also mean more security features, more customization, and so forth. These days professional may even mean less advertising and spying (which today are the same thing). It could mean less quality variance over temperature and age (similar to industrial quality), and there are some consumer products that just don't work well if left in the sun on a hot day.

          At a previous job we used compact flash for our device storage on a medical device. It was amazing how lower quality those things were w

    • There are plenty of areas in personal tech that could certainly use a huge jump in speed and/or density.

      Virtual reality, for example - a tenfold (or more) increase in graphics processing power would make personal VR amazing instead of just fun. Standalone setups like the Oculus Go could have 4k-per-eye graphics, with high frame rate and roomscale tracking.

    • Re: (Score:2)

      by AHuxley ( 892839 )
      Not with 5K and then 8K games.
      Code in ray tracing and its back to needing a new generation of GPU and CPU support.
      To keep up with 60 fps. To get back to over 100 fps.
      • 8K in a 17" monitor? more fps that is visible? :D

        • Re: (Score:2)

          by AHuxley ( 892839 )
          People playing games at home do expect their next GPU to offer 4K support, a great refresh rate and always support the needed frame rate.
          Then a move to 5K and later 8K support..
          Time to design a better GPU and CPU.

    • If you think what we have is "good enough" for scientific uses, you have never worked in a big research project.

  • Better For GPU Tech (Score:5, Interesting)

    by mentil ( 1748130 ) on Sunday December 02, 2018 @08:02AM (#57735898)

    This reminds me of what happened with NAND (i.e. flash memory) a few years ago. Ever-smaller transistors hit a wall due to endurance problems (each one could only be reprogrammed a few hundred/thousand times), so they went back to larger transistors but started stacking them into layers. Now we're at ~96 layers, and it's expected that a few thousand layers is feasible.

    The problem with layering in CPUs is how hot each layer gets, and adding new layers is unlikely to help single-core performance beyond what cache can do. So, we're going to end up with low-clockspeed (to minimize heat) thousand-core CPUs... which will actually be perfect for GPUs, not so much for that single-threaded productivity task. I could also see this being used for HBM, which is already stacked.

    • Re:Better For GPU Tech (Score:5, Interesting)

      by drinkypoo ( 153816 ) <drink@hyperlogos.org> on Sunday December 02, 2018 @08:14AM (#57735930) Homepage Journal

      The problem with layering in CPUs is how hot each layer gets,

      Chips will have liquid cooling integrated into the die itself eventually. It's just a matter of time. ISTR some articles on this already, and that if you make water channels so small that only one water molecule can fit through at a time, there is actually less resistance to flow. So maybe they'll have MEMS-built channels on the actual die, and a pump or a heat pipe system...

      • Re: (Score:2)

        by HiThere ( 15173 )

        If you're going to do that, why not use liquid Nitrogen, and high-temperature super-conductors. ISTR that it's fairly cheap to generate liquid Nitrogen locally. (You wouldn't need medical grade.)

        It's a good thing we're talking about hardware a decade from now, though, or that suggestion would be impractical.

      • At some point (not far away these days) the cooling system starts to become as large as the chips it is cooling, and then there isn't a lot of benefit for higher power densities.

        I think the energy per gate switch has to come down. There is a fundamental (I think) limit of several times thermal energy (~1/40ev at room temperature). If you cool below room temperature the Carnot efficiency of the refrigerator keeps you from going much further.

        I don't know how close current devices are to KT energy these days.

    • The reason chips get hot is because semiconductors resist electron flow and get hot. If these new transistors (tubes?) don't contain semiconductors then they won't generate the heat. Also metal can take the heat better than semiconductors, so you can run hot.

      • Metal can flow and deform more easily than semiconductors when hot.

      • Re: (Score:2)

        by HiThere ( 15173 )

        FWIW, tubes used to get too hot to touch. Of course, if there's no emitter, then you might not have that problem. And there better not be, or you'll have an impossibly high failure rate. (They seem to be talking about field effects.)

    • Re: (Score:2, Insightful)

      by ledow ( 319597 )

      You aren't gonna get into the double-digit GHz with standard single-core performance with an ordinary device (i.e. not liquid-cooled superconducty stuff).

      That's just a fact of life, and physics. And such, we need to parallelise everything we can. There's nothing you might need to perform "ordinary" computing (including games) that can't really be parallelised well. Almost everything can. But we haven't bothered.

      The wake-up call was 3D graphics, yes, but the reality is that everything needs to be threade

      • Re: (Score:2)

        by HiThere ( 15173 )

        It *IS* tricky to program that way. But message passing of invariants is a way to limit the difficulty. Several modern languages are making attempts in that direction, but most of them make it difficult to do NxN independently executing processes without falling back on something like UDP. (TCP is too heavy, but UDP needs a simple message verification protocol tacked on top of it.)

      • If you're single-threading in this day and age your days are numbered.

        Not every problem is parallelisable. I think there's even a complexity class of some sort about that.

    • Don't forget that a lot of this need for caching, and multiple tiers of caching, is because of terribly optimized code. Look at typical Ms Office applications today - they don't do more than they did 15 years ago in practical terms and yet they feel slower today on what are essentially supercomputers and that's because of all the fluff, and the change in programming styles.

      • Do you even use MS Office, or are you just spreading hearsay? On my nine-year old dev machine, Word 2010 launches in half a second and uses about 10MB of RAM with an empty document. Seems pretty svelte by modern standards.

        I do think the overall point you're making is valid, just not the particular example used. You can look at Electron-based apps as the most egregious offenders in this regard. For instance, GitKraken takes about 12 seconds to load, and chews up over 450MB, which is just shy of twice the

        • Yes I use it at work. Note that Office will preload by default when you install it. So it's in RAM waiting for you to start it up so that it feels snappier. Several programs do this. I disable that when I can because it can noticeably slow down you login. I routinely see hiccups when scrolling through pages these days (on OSX), even with 8GB of RAM and a solid state drive. In the past these applications would fit under 1MB.

          • Fair enough - maybe OSX performs a lot worse? Guess I wouldn't be too surprised at that. I've disabled any but essential tasks at startup, as I find it pretty annoying when they do that. Feels like "cheating" to me - trying to cover up slow startup time. So I think it really does launch that fast, as far as I can tell.

  • Temp (Score:5, Interesting)

    by markdavis ( 642305 ) on Sunday December 02, 2018 @08:15AM (#57735932)

    >"The nanoscale air gap is less than the mean-free path of electrons in air, hence electrons can travel through air under room temperature without scattering... "

    And what about when not at room temperature? Seems like that little disclaimer could be what makes the whole thing impractical. A chip/board isn't going to be made up of ONLY these "metal-air" transistors, so it is going to generate a significant amount of heat or be near something that does. Plus, there is the overall environment in which the device will be used that needs to be considered. The article doesn't elaborate on this at all.

    • I would guess that the higher conductivity of metal means the resistance related losses are lower, and thus faster and less heat.

      There is, of course, the problem of voltage breakdown if things get too small, and potentially, at very small scales (people talking about only room for one water molecule) electrons tunneling (due to quantum effects, you can't be sure if the electron is in the metal or in Schroedinger's cat).

      It is certainly interesting, but is it practical?

      • Re:Temp (Score:5, Insightful)

        by Ol Olsoc ( 1175323 ) on Sunday December 02, 2018 @09:56AM (#57736176)

        potentially, at very small scales (people talking about only room for one water molecule) electrons tunneling (due to quantum effects,.

        I believe this is based on quantum tunnelling. Fowler–Nordheim tunnelling in tungsten and gold devices, while using Schottky emission in platinum device. Whether this is because of the electric field strength needed is lower in platinum device isn't clear, as increasing the field strength tends to favor FN tunnelling.

        Its pretty interesting stuff, but will it work? That would be pretty cool if it does.

      • Re: (Score:1)

        by Anonymous Coward

        Actually, the problem with these devices, as tested by NASA for space exploration is that, like vacuum tubes, they get so hot that the metal ablates and has a finite life expectancy that's much shorter than with semi-conductors. Electron streams are hot because the electrons are moving very quickly, so even though these devices can operate at 300GHz+, they are essentially frying themselves in the process.

    • lol it does not elaborate at all. Is that why its generating so many comments?
      • Is that why its generating so many comments?

        A Betteridge to you sir!

        No. The large number of comments is because it is a slow news day.

    • Re: (Score:1)

      by Anonymous Coward

      >"The nanoscale air gap is less than the mean-free path of electrons in air, hence electrons can travel through air under room temperature without scattering... "

      And what about when not at room temperature? Seems like that little disclaimer could be what makes the whole thing impractical. A chip/board isn't going to be made up of ONLY these "metal-air" transistors, so it is going to generate a significant amount of heat or be near something that does. Plus, there is the overall environment in which the device will be used that needs to be considered. The article doesn't elaborate on this at all.

      The reason they specify room temperature is really just to note that no special temperatures are required to gain the effect required. Sometimes things need to be super-cooled (or heated) to work properly. This does not.

      Its not uncommon to see this denoted when being briefed on this type of science.

      • >"The reason they specify room temperature is really just to note that no special temperatures are required to gain the effect required. Sometimes things need to be super-cooled (or heated) to work properly. This does not."

        Yeah, I was wondering if that is what they meant, but it is very unclear.

  • Questionable headlines (Score:3)

    by WoodstockJeff ( 568111 ) on Sunday December 02, 2018 @09:23AM (#57736084) Homepage

    Why do Slashdot editors insist on making headlines into questions that aren't answered in the article? A headline is a super-short summary the story. The story isn't a question, so the headline shouldn't be, either.

    The story is, "Researchers believe new metal-air transistors could continue Moore's Law". It isn't a debate on this belief of those researchers.

    Oh, wait - this is a click bait tactic used to make something seem more interesting than it really is...

    • Re:Questionable headlines (Score:5, Interesting)

      by Whibla ( 210729 ) on Sunday December 02, 2018 @10:06AM (#57736218)

      Why do Slashdot editors insist on making headlines into questions that aren't answered in the article?

      Perhaps they were hoping to stimulate a discussion between knowledgeable posters, one which weighed the pros and cons of this new (take on) tech, and perhaps arrived at an answer to that question. They might also touch on other, unasked, questions such as whether such tech is desirable, and what we might use it for - something a couple of people have attempted.

      The story is, "Researchers believe new metal-air transistors could continue Moore's Law". It isn't a debate on this belief of those researchers.

      "It", whatever "it" might be, may not be a debate about the belief of the researchers but if not it's almost certainly a debate about the reasons for their belief. I'd suspect most people who browse here would instinctively fill in the blanks: most, not all - there's always a few who come here to find something to be outraged about, and they can usually find something, then rage about it, while contributing absolutely zero to the discussion.

      Oh, wait - this is a click bait tactic used to make something seem more interesting than it really is...

      I'm sorry you find this story about new technology uninteresting. Leaving aside the possible reasons for that, one still has to wonder at your expectations when you label the summary as 'click bait'. What do you think people come here for, other than the comments, if not to click on the links to the stories behind the headlines? Click bait kind of implies the article is about nothing and that's certainly not the case here ... well, in my opinion anyway.

      I'll will add, my main skepticism about the article was regarding the following: "Devices can be built on ultrathin glass, plastics, and elastomers... So they could be used in flexible and wearable technologies." Hmm, 35nm airgaps in bendable materials - that sounds like a recipe for errors to me, and that's assuming they can solve the electrode tip melting problem. However, the timeline given in the article is, if not 'realistic', long enough that one cannot discount their ideas and short enough that it gives us something to look forward to. I for one will be interested to see how they progress!

      • Re:Questionable headlines (Score:4, Informative)

        by Solandri ( 704621 ) on Sunday December 02, 2018 @02:57PM (#57737320)

        I'll will add, my main skepticism about the article was regarding the following: "Devices can be built on ultrathin glass, plastics, and elastomers... So they could be used in flexible and wearable technologies." Hmm, 35nm airgaps in bendable materials - that sounds like a recipe for errors to me

        The bend radius for things which are "flexible" on the human scale is so large that there's almost no bending on the nanoscale. Same reason fiberglass bends so easily. Glass in your experience with human-size windows shatters rather easily rather than bends. That's because a 1 cm thick window bent with (say) a 1 meter radius results in the the two sides differing in length by 1% before it breaks. But if you shrink the glass down to the 10 um (0.01 mm) thick, suddenly you can bend it in a 1 mm radius before it hits your 1% threshold. And the result is glass which behaves like cloth [youtube.com]. (If you ever get your hands on an individual fiberglass fiber, you can in fact break it by tying it into a knot and tightening until the bend radius becomes too small for the glass to withstand.)

        For materials like silicon, the rigid crystalline structure results in shattering at very small amounts of flex.

        And I have to disagree with you, the headline was click-bait. It asked a question which TFA does not answer. TFA uses a non-click-baity headline: "New Metal-Air Transistor Replaces Semiconductors - A novel field emission transistor that uses air gaps could breathe life into Mooreâ(TM)s Law." That makes it clear the future potential is unknown, whereas the click-bait slashdot headline implies you'll get the answer to the question it asks if you read TFA. The click-bait headline was added by the slashdot editor.

        • Re: (Score:2)

          by Whibla ( 210729 )

          Thank you, that was a useful reply. (And sorry it took me so long to say so - took a couple of days away from the internet.)

          My concern, if you can call it such, wasn't so much about fracturing though as it was about uneven bending between the electrodes bridging the gap. I have been led to believe that materials at this scale can behave slightly more unpredictably, presumably partly because of the relative proportions of (im)perfectly ordered atoms at small vs large scale, so either your materials manufactu

  • Moore BS (Score:2, Insightful)

    by 110010001000 ( 697113 )
    1) Moore's Law is already dead
    2) Air-gap transistors have been around since mid 1990s.
    3) No offense, but it is doubtful such a breakthrough would come from some university I have never heard of in Australia. Based on their Wikipedia page they are known for art and design.

    • Re: (Score:1)

      by Anonymous Coward

      3) Not particularly offensive. Just arrogant.

      It would be really helpful if you could read a charter of universities.. just their names would be enough.. and thusly enable them to realise more breakthroughs - purely by that fact that you will then have heard of them.

      They've invented stuff before.. world's first rechargeable proton battery, thinnest hologram.. but now you've heard of them, they are unfettered and the sky is the limit.

      If your personal experience is truly the universal gatekeeper of probabilit

    • Moore's law hit an economic wall not a physical one. The cost of R&D and of fab plants has also been growing exponentially, doubling every 30 months. The market for chips also grew quite a lot in the last 45 years. However not nearly as fast as the cost of fabrication. So what we saw was less and less fab plants on the leading edge. We are now down to two companies pushing the envelope for large complex processors and it looks like one (Intel) is going to take a small pause.

  • Tunneling (Score:1)

    by Anonymous Coward

    In scanning tunneling microscopy under vacuum, the metal tip usually had to be a few nanometers away to observe a decent tunneling current under normal bias. Tunneling 30-nm in air? I am not sure how that makes sense. Best read the paper when I get the opportunity.

  • Hmm, how do you make a CMOS pair out of that transistor?

  • I wonder what Microsoft will think up to waste all the additional compute power? Maybe preemptive aeroglass?

  • People are so hung up over “Moore’s La (Score:4, Insightful)

    by 93 Escort Wagon ( 326346 ) on Sunday December 02, 2018 @01:44PM (#57737066)

    It seems rather silly. It’s not a statement of some absolute scientific truth - nothing really depends on it holding true or not. If Moore’s Law stops being true, it’s not as if Intel or TSMC or Samsung is going to be shuttering factories because their fabs won’t work anymore. Jony Ive won’t descend into madness because he can’t make things any thinner. Nothing practical will actually change, and technological development will continue to progress.

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