back to article A carbon-nanotube RISC-V CPU blinks into life. Boffins hold their breath awaiting first sign of life... 'Hello world!'

“Hello, World! I am RV16XNano, made from CNTs.” That’s the friendly message emitted by a RISC-V-based chip made entirely out of carbon nanotubes (CNT) and revealed on Wednesday. More than 10,000,000 CNTs were used to form 14,702 CMOS carbon-nanotube field-effect transistors (CNTFETs), arranged in 3,762 digital logic blocks, …

  1. elkster88

    So it is possible...

    For a bunch of CNTs to do something useful after all.

  2. Conundrum1885

    Re. So it is possible...

    CNT based sensors seem to work well but yes this is the first time such a complex structure has been made.

    Incidentally it is said that the very first CPU was made by cutting and pasting physical pieces of film, to make the mask that was later optically miniaturized and used.

    1. Korev Silver badge

      Re: Re. So it is possible...

      Thanks for the Intel

    2. Muscleguy Silver badge

      Re: Re. So it is possible...

      Yup, just like you can use an old style photo enlarger to make bigger copies of negatives onto paper so you can use different optics to dial a source down in size. It was a pretty obvious route for at least the initial work.

      Disclosure: in my Honours and PhD I printed a LOT of pictures, though I did have technical help for a decent proportion. But I have earned my spurs in photo printing in a darkroom.

      1. Dazed and Confused

        Re: Re. So it is possible...

        When I worked in a semiconductor research lab (donkey years back, in the days of 3.5um) the chip designs would end up on big film sheets ready to be optically shrunk to make the actual masks.

  3. Wiretrip

    So glad they didn't go for Copper Nanotubes ;-)

    1. Queeg

      I Cu what you did there :)

    2. Sir Runcible Spoon
      Thumb Up

      That deserves a lot more upvotes than I can supply, well played Sir.

      1. ShadowDragon8685

        Fear not; I have your back.

    3. Michael Wojcik Silver badge

      I read of a project to create nanotubes with one of the actinides, but apparently the results were pants.

  4. Andy 73

    But how fast does it clock?

    See title....

    1. Dave Pickles

      Re: But how fast does it clock?

      From the article their demonstration ran (?) with a 10KHz clock, but experiments on individual gates maxed out at 1.19MHz.

  5. macjules

    You missed a bit!

    Sometimes the structure of the carbon atoms results in structures that have unwanted metallic properties, such as high conductance. This can lead to current leakage and faulty chip operation, which you don't want in a processor.

    One of the more interesting aspects of the research is exactly how they countered the metallic carbon nanotubes. They mapped out every possible scenario where the metallic carbon nanotubes interfered and ran simulations to find all the different gate combinations that would be robust or wouldn’t be robust to any metallic carbon nanotubes, which they then built into the chip design automation.

  6. Unicornpiss


    They washed it with a polymer and a solvent because you just can't do much with a dirty CNT..

  7. Forum McForumface

    One for Rocky Horror fans

    What’s a CNT? Three quarters of a...

    1. Sir Runcible Spoon

      Re: One for Rocky Horror fans


      1. The Oncoming Scorn Silver badge

        Re: One for Rocky Horror fans

        Whats grey & comes in pints...


        1. Sir Runcible Spoon

          Re: One for Rocky Horror fans


  8. 2+2=5 Silver badge

    Tricky to work with

    > Carbon nanotubes are tricky to work with. Sometimes the structure of the carbon atoms results in structures that have unwanted metallic properties, such as high conductance.

    Flaws like high conductance can make the resulting chip look silly. Worse is when only one end of each alternate carbon nanotube is attached to the silicon, leaving a loose end to stick up: this is even cilia.

  9. Tom 7 Silver badge

    Well this has got to be one of the most puerile comments threads I've seen on the Register .

    Thanks, bloody need it at the moment!

    1. Fungus Bob

      Re: Well this has got to be one of the most puerile comments threads I've seen on the Register .

      CNT agree more...

      1. J. Cook Silver badge

        Re: Well this has got to be one of the most puerile comments threads I've seen on the Register .

        It's a little RISC-que?

  10. c1ue

    If I'm understanding the paper right, 10,000 digital logic gates were in the die spec of which 3762 wound up being used.

    The process sounds like an FPGA type design.

    Maybe 38% transistor utilization is good for FPGA; it isn't good at all vs silicon.

    It also isn't clear how well the utilization can scale up - really depends on the type and nature of the failures causing the low utilization.

    Cool, but a semi factory equivalent of Heathkit.

    Modern chips comprise hundreds of millions to billions of functional transistors.

    1. Michael Wojcik Silver badge

      So, you're telling us that this new technology, at an early stage of development, is not yet competitive with our existing half-century-old technology?

      Well, I for one am shocked. Shocked, sir. I demand we cancel all further research into carbon nanotubes and obliterate all mention of it from the history books.

    2. Mark192

      My horse is faster...

      ...than this motorised carriage.

    3. Tom 7 Silver badge

      Not quite - FPGA is kind of like lots of devices that can be joined together in a miriad of ways as you choose, This is an array of device some of which may work, and those working ones are then wired together to make the final working circuit. Think of it as a massive breadboard that is populated with a load of components bought from a dime store. The components are fixed in before you can test them so you have to use whats there.

  11. Conundrum1885

    Carbon memory

    Distantly recall an idea to use vertical CNT arrays as nanoscale memory.

    The plan here was similar, fix in place then lay down the interconnects and R/W logic, but ion implant Zn or some other metal so that one metal atom ends up in each tube, then use standard wear leveling and error correction so more than one CNT stores each bit, yet also acts as a CRC for another elsewhere.

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