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One-Atom-Thick Silicene Transistors May Lead To Dramatically Faster Chips

Posted by Soulskill on from the ever-smaller-ever-faster dept.

Zothecula writes: As recently as 2010, human-made silicene – an atom-thin form of silicon – was purely theoretical. But now the exotic material has been used to make transistors, and researchers have found that silicene's electrical properties lend it extraordinary potential in powering the next generation of computer chips. The new method (abstract) of creating the silicene reduces its exposure to air. "To start, the researchers let a hot vapor of silicon atoms condense onto a crystalline block of silver in a vacuum chamber. They then formed a silicene sheet on a thin layer of silver and added a nanometer-thick layer of alumina on top. Because of these protective layers, the team could safely peel it of its base and transfer it silver-side-up to an oxidized-silicon substrate. They were then able to gently scrape some of the silver to leave behind two islands of metal as electrodes, with a strip of silicene between them."

34 comments

  1. By the time this gets fabbed... by Anonymous Coward · · Score: 0

    they'll be on to the next dope technique.

    1. Re:By the time this gets fabbed... by ShanghaiBill · · Score: 4, Insightful

      they'll be on to the next dope technique.

      That is the way it works. R&D is a pipeline:
        Basic-Research -> Applied Research -> Product Development -> Manufacturing -> Applications
      Silicene is moving from "basic" to "applied" research, and is a long way from actual applications.
      But we need to keep feeding the pipeline if we want progress to continue.

    2. Re:By the time this gets fabbed... by Anonymous Coward · · Score: 0

      That is the way it works. R&D is a pipeline:

        Basic-Research -> Applied Research -> Product Development -> Manufacturing -> Applications

      That pipeline looks very uneven to me.
      I feel like the two steps could easily span over decades while the last three steps typically fits in a 5 year time.

    3. Re:By the time this gets fabbed... by Anonymous Coward · · Score: 0

      So? Nobody ever said each step required the same time.

    4. Re:By the time this gets fabbed... by Anonymous Coward · · Score: 0

      Yes, but pretty much the same was said of GaAs and look where that went: nowhere.

  2. this vs graphene. by RyuuzakiTetsuya · · Score: 3, Insightful

    I'm curious, which one gets fabbed first?

    I'd be willing to bet on graphene, since we've had it for years. However, silicene might make it first because it seems like despite the fact that making it is more involved, doing it at industrial scales might be easier.

    --
    Non impediti ratione cogitationus.
    1. Re:this vs graphene. by ShanghaiBill · · Score: 5, Informative

      I'm curious, which one gets fabbed first?

      Silicene has a tunable band gap. That makes it more useful for transistors. But, unlike graphene, it will spontaneously oxidize. So there are some big problems to iron out with both graphene and silicene. This research is mainly about dealing with the oxidation problem. If we can solve that, then silicene will likely "win" the race to fabrication.

    2. Re:this vs graphene. by infogulch · · Score: 4, Informative

      The problem is graphene has no band-gap, so it's pretty useless as a transistor (unless it's heavily doped I suppose). That's not to say it can't be doped, or that there aren't any uses for graphene other than transistors.

    3. Re:this vs graphene. by pla · · Score: 5, Informative

      Graphene has the unfortunate property that transistors using it don't actually have an "off" mode - Just a "low" and "high". So although it might give us crazy-fast switching times, it will leak current worse than an XFinity modem. But hey, we all miss the good ol' days of using our P4 gaming rigs as space heaters, right?

      Silicene, by comparison, does have a tunable band-gap, meaning that it should get around that limitation of graphene.

    4. Re:this vs graphene. by Crashmarik · · Score: 1

      Silicene hands down. Silicon is incredibly well understood and already has a tremendous infrastructure in place to support it.

    5. Re:this vs graphene. by ArcadeMan · · Score: 2

      But with the high cost of drugs, won't that make it even more expensive?

      --
      Get free satoshi (Bitcoin) and Dogecoins
    6. Re:this vs graphene. by Neil+Boekend · · Score: 1

      Silicon and silicene are about as different as coal and diamond. Much of the experience with silicon is as applicable to selicene as it is to graphene.

      --
      Well, I might have a way, but it only works on a semi spherical planet in a vacuum.
    7. Re:this vs graphene. by Neil+Boekend · · Score: 1

      It is possible to work under a nitrogen or argon cover gas. That won't change the manufacturing process all that much.

      Transport of the wafers from one point to the other is the biggest issue. However, if the wafer trays are redesigned to prevent leaks then this isn't an issue. I expect that manual wafer handling is not done in most modern fabs so a nitrogen or argon cover gas won't change much in the movement to and from the trays.
      Racks with wafer trays may need a nitrogen downflow instead of the cleanroom air downflow they have now. This will require some rather large changes but nothing a bleeding edge CPU fab isn't used to. Much of the manufacturing machines will have to be replaced or modified anyway for graphene, just like with an Intel "Tick" (increasing the density).

      The next generation of ASML wafer steppers (NXE) will have no internal oxidation issues. They work in vacuum because the extreme UV won't go through air anyway.

      After the wafer steppers there is cutting, diebonding, wirebonding and packaging. I assume these are all possible under cover gas, including the transport between the machines.
      In fact, the die- and wirebonding on discrete transistors is already done under a nitrogen cover gas. The copper coated leadframe wouldn't survive the 310 C bonding temperature if it had oxygen available. I assume that CPU wirebonding has similar requirements. You need the same type of gold wire bonded to the same type of silicon surface so the same temperatures will be required.
      (I have seen a few wirebonding machines operarte without nitrogen flow. The copper coated leadframe turns black in seconds and the wires will not bond anymore and you have to re-insert the 23 mu wire by hand.)

      In short: oxidation seems a solvable problem, form an armchair engineer's perspective.

      --
      Well, I might have a way, but it only works on a semi spherical planet in a vacuum.
  3. Process by Anonymous Coward · · Score: 0

    To start, the researchers let a hot vapor of silicon atoms condense onto a crystalline block of silver in a vacuum chamber.

    Ok, block of silver + coating of silicon.

    They then formed a silicene sheet on a thin layer of silver

    Repeating the process above, but on a not-block of sliver?

    and added a nanometer-thick layer of alumina on top.

    On top of which, the block of silver or the thin layer of silver?

    1. Re:Process by NMBob · · Score: 1

      The first picture in the abstract link shows it. The description above is a bit confusing.

    2. Re:Process by bugs2squash · · Score: 1

      Don't they need three electrodes for a transistor ?

      --
      Nullius in verba
    3. Re:Process by Anonymous Coward · · Score: 0

      Yes, the journalist definitely wasn't following. There is a nice diagram included in the linked abstract, albeit a bit small, that shows the actual process. There is no block of silver, there's a block of mica with a thin layer of silver. Silicene is deposited on that, followed by the alumina layer. Then the silver layer with all the other stuff on top of it is detached from the mica, flipped and attached to the oxidised silicon substrate.

  4. DUH by Anonymous Coward · · Score: 0

    smaller has always been faster

    1. Re:DUH by Anonymous Coward · · Score: 0

      smaller has always been faster

      That's what your mom said.

    2. Re:DUH by ArcadeMan · · Score: 2

      You just confessed to having a small dick and suffering from premature ejaculation. Congratulations!

      --
      Get free satoshi (Bitcoin) and Dogecoins
    3. Re:DUH by sexconker · · Score: 1

      You just confessed to having a small dick and suffering from premature ejaculation. Congratulations!

      Don't forget the worst bit - he fucked AC's mom. She's straight 90s OOGLAY.

  5. Mechanical stability? by DoofusOfDeath · · Score: 2

    I don't have any kind of physics background, so maybe someone can explain this to me.

    If you have a single-atom-thick layer of some material, how much of a bump can it withstand before the sheet gets ripped apart? I would imagine even a small vibration of the material, such as dropping the overall package on a desk, would ruin it.

    1. Re:Mechanical stability? by Anonymous Coward · · Score: 1

      A piece of wet tissue paper is exceedingly fragile to handle.

      Now place that piece of tissue paper in the middle of a thick book and close it. You toss the book in your backpack and stomp on it, and the tissue paper will be still be intact.

    2. Re:Mechanical stability? by unixisc · · Score: 1

      Wouldn't it be deposited on some sort of substrate to avoid exactly that problem? Not to mention, if made into an IC, it would need to be packaged, and there, thinner would be better in terms of the packaging. However, the handlers would have to be really delicate to handle such thin die. In short, packaging would be a lot more expensive, unless they figure out a way to get volumes out of this one

    3. Re:Mechanical stability? by BoRegardless · · Score: 1

      Going to have to be a lot of error checking to get fault tolerant.

    4. Re:Mechanical stability? by kesuki · · Score: 2

      as i understand the ceramic or silver substrate will bond it and make it stable enough for use as a microchip.

      --
      https://www.gnu.org/philosophy/free-sw.html
    5. Re:Mechanical stability? by denobug · · Score: 1

      In short, packaging would be a lot more expensive, unless they figure out a way to get volumes out of this one

      Getting volumes out is exactly what the manufacturing engineering will be doing, and usually involves a bigger slice of wafer to increase yield.

  6. Another one? by fey000 · · Score: 1

    Now it's just getting sili

  7. Re:Good...I think by crypticedge · · Score: 1

    Wrong story.

  8. Very very small rolling pins? by CODiNE · · Score: 3, Funny

    How does one get the initial flat surface to deposit things on?

    --
    Cwm, fjord-bank glyphs vext quiz
  9. Crystalline Ag by Anonymous Coward · · Score: 0

    So what is amorphous silver (assuming a solid)?

    1. Re: Crystalline Ag by Anonymous Coward · · Score: 0

      Amorphous Silver means the silver atoms are jumbled together without any coherent structure or pattern. Most glass is amorphous. That's why it shatters I to a myriad of different shapes and sizes when broken.

    2. Re: Crystalline Ag by Anonymous Coward · · Score: 0

      The silver is not amorphous - the RHEED pattern shows local crystallinity, but it does not show long range order - it is polycrystalline.