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Future Phones May Use Vacuum Tube Chips As Silicon Hits Moore's Law Extremes ( 147

An anonymous reader writes: A team of researchers want to replace transistors with vacuum tubes. Vacuum tubes are nothing new, however the ones in development at Caltech's Nanofabrication Group are a million times smaller than the ones in use 100 years ago. "Computer technologies seem to work in cycles," Alan Huang, a former electrical engineer for Bell Laboratories, told the New York Times. "Some of the same algorithms that were developed for the last generation can sometimes be used for the next generation." Dr. Axel Scherer, head of the Nanofabrication Group, said to the New York Times on Sunday, "Ten years ago, silicon transistors could meet all our demands. In the next decade, that will no longer be true." He argues silicon transistors can only take us so far. Vacuum tubes, for comparison, use tiny metal tubes that can control the flow of electricity. They're especially intriguing to researchers as they can provide a better solution to silicon transistors as they can consume less power and take-up a much smaller footprint. The report mentions they have the potential to bring an end to Moore's Law, even if silicon transistors show no signs of disappearing. For example, Lockheed Martin published new cooling methods in March that could help cool chips with tiny drops of water. With that said, Boeing has invested in researching vacuum tube chips. They may appear in the aviation industry before 2020, but it's unlikely we'll see Caltech's research appear in smartphones anytime soon.
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Future Phones May Use Vacuum Tube Chips As Silicon Hits Moore's Law Extremes

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  • by sconeu ( 64226 )

    I wonder if they are as resistant to EMP as old school tubes were.

    Or is that simply a factor of size?

    • EMP resistance (Score:5, Informative)

      by Firethorn ( 177587 ) on Monday June 06, 2016 @06:21PM (#52262829) Homepage Journal

      No, they wouldn't be as resistant on average, because yes, the biggest factor is size.

      That being said, EMP resistance gets 'complicated', and it's easier to stick a small chip inside a faraday cage than a room sized monster.

      • by JavaBear ( 9872 )

        The EMP can cause havoc to the surrounding circuitry as well.

      • I remember back in the early and mid-90's the idea was to include micron-size vacuum tubes in integrated circuits in order to cut down the reverse-current to a level that semiconductor diodes could not do it.

        Those tubes were functionally only diodes and the idea was to use the strong electric field at the tip of a very small cone to achieve cold electron emission. Imagine hollowing out a half-sphere and then add a cone with the tip at the center of the sphere. Now apply a voltage between the two. The electr

      • That being said, EMP resistance gets 'complicated', and it's easier to stick a small chip inside a faraday cage than a room sized monster.

        Is it even relevant to portable devices? I always thought that the mechanism of EMP (large area nuclear-generated EMP at least) largely relied on conductive loops with significant area, such as loops in power grids. Pocket devices might not necessarily have enough area for a variable magnetic field to induce significant damaging currents.

        • Relevant to portable devices? Yes. How vulnerable? Complicated.

          You see, with an EMP it's typically a single pulse. You don't actually need a loop. The emp will 'shove' electrons one way or another, creating a voltage spike over [i]any[/i] wire of sufficient length along the wave of travel of the event. IE a line running perpendicular to the event would end up being a circle but not experience any significant voltage(0 for a theoretical superconductor of zero width), but one running from the epicenter

    • by gweihir ( 88907 )

      It is also a factor of size, but vacuum tubes react differently to EMP. The thing is FETs suffer damage to the gate-insulation on EMP due to high voltages. Vacuum tubes are on some abstraction level similar to FETs, but they use a vacuum for that insulation and that cannot be damaged directly. Still, if the EMP is strong enough, it may dislodge metal particles due to high currents and those do damage, and more so with smaller vacuum tubes. They should still be a lot more EMP resistant.

  • Hmmmmmmmm. Or should I say "hummmmmmmm..."

    • by Anonymous Coward

      You just wrote tran-sisters. Think about that.

    • Looks like someone's fishing for grant money.
    • That is exactly what my tube amp says...."hummmmmmmm..."

      • Time for new filter caps?

        • Likely so.. Getting a good filter cap that's gong to work at 800 Volts is going to be fun though. Electrolytic's don't like over voltage about as much as reverse voltage... KAPOW...

          • by BlueStrat ( 756137 ) on Monday June 06, 2016 @08:37PM (#52263589)

            Time for new filter caps?

            Likely so.. Getting a good filter cap that's gong to work at 800 Volts is going to be fun though. Electrolytic's don't like over voltage about as much as reverse voltage... KAPOW...

            Vacuum tube amplifier tech here with 40+ years experience.

            Here's a 25uF @ 800V/900V-surge "firecracker" style.


            More stuff here.


            Even more here.


            Another option is to series-connect two 450V or 500V capacitors to meet the 800V minimum rating requirement. I recommend placing a 100K Ohm 1-watt metal-film resistor across each of the two series-connected capacitors to make sure the voltage across each capacitor divides equally, as the ESR (effective resistance) of individual capacitors varies slightly from unit to unit and causes the voltage to divide unequally without the resistors which could possibly result in one of the capacitors "seeing" excess voltage. Usually not a problem, but why take a chance with a shortcut?.

            The resistors also act as a safety feature as "bleeder" resistors to prevent accidental shock from a stored charge long after power has been removed by slowly discharging ("bleeding") the capacitors after power is removed.

            As a safety tip, *always* keep one hand in your pants-pocket when performing tests/adjustments on live circuits to prevent completing a path to ground through one's chest. Human hearts don't take kindly to high voltage passing through them.

            Be careful and good luck!


            • by HornWumpus ( 783565 ) on Monday June 06, 2016 @08:44PM (#52263635)

              And stand on the same side foot as the hand you're working with. Ground path not through chest.

            • Mod parent up 'Informative'. Great stuff.

              AES ( []) is an excellent resource; one of my favorite parts vendors for tube amp builds/mods. No relationship, just a happy customer.
              • Mod parent up 'Informative'. Great stuff.

                AES ( []) is an excellent resource; one of my favorite parts vendors for tube amp builds/mods. No relationship, just a happy customer.

                Thank you kindly, Sir!

                Other great resources for tube amplifier parts, supplies, kits, pre-built and fully populated "drop-in" turret boards.

                Ted Weber Speakers (and tons of amp parts, kits, etc) in Kokomo, IN. Weber speakers are legendary and Fender uses Weber speakers in their "signature model" line of "tweed" '50s-style amplifiers..


                Watts Tube Audio in Saint Petersburg, FL.They offer loaded drop-in turret boards for many classic amp designs/brands as well as tons and tons of other t

            • Oh, forgot to mention that when placing two capacitors in series the capacitance value divides, so select a capacitance value for each of the two series caps that is twice the required capacitance value. Example; Two 50uF caps in series results in an effective capacitance value of 25uF.


              To HornWumpus:

              Standing on one foot while testing a live circuit is not necessary or advisable as one is far more likely to lose one's balance and fall into the circuit under test.

              It *is* advisable to wear reasonable footw

            • When you series connect two capacitors to double the max working voltage you half the capacitance. So use two capacitors double the size you need... it gets big and bulky fast.

              • No buliker than the other way. The limit on capacitors is generally energy stored per unit volume. It makes little difference having two smaller ones versus one large one except for the amount of packaging.

                • My point was that hooking two capacitors in series doubles the working voltage but halves the total capacitance. The total charge in coulombs is still doubled. But the capacitance is halfed. To get double the voltage and have the same capacitance you need four times as many capacitors. And get four times the charge (I * T, aka big spark).

            • It's not voltage that kills, it's the current.... But at 800 volts, generating enough current to shutdown one's heart is pretty much a given.

              Better tip.... Don't work on tube circuits which are powered or have recently been plugged in unless absolutely necessary (and it rarely is if you think about what you are doing), in fact, don't ever have it plugged in and the cover off at the same time. Secondary tip: Always discharge capacitors and verify they are discharged using a screwdriver with an insolated

      • That's what my door says, with a smug sense of self satisfaction at the knowledge of a job well done.

        As the door closed behind them it became apparent that it did indeed have a satisfied sigh-like quality to it. “Hummmmmmmyummmmmmm ah!” it said...

  • by avandesande ( 143899 ) on Monday June 06, 2016 @06:20PM (#52262823) Journal
    "but it's unlikely we'll see Caltech's research appear in smartphones anytime soon."

    I am reading on a phone right now you insensitive clod!
    • It does seem strange that they say it will first be used in airplanes, and later in consumer electronics. That's exactly the opposite of how it normally goes: even the latest airplanes are always using technology from at least a decade ago. They need everything to be proven first. It's not uncommon for an airplane to use 3.5 inch floppy discs to update the navigation database, although most are switching to CD-roms now. Most piston engine airplanes still have an oldfashioned carburettor and you need to turn

  • The Fallout series had it right?
  • Call me a geek (Score:5, Interesting)

    by Tx ( 96709 ) on Monday June 06, 2016 @06:36PM (#52262939) Journal

    Call me a geek if you like, but I really enjoy watching this video [] of a guy hand-making triode valves (AKA vacuum tubes), it's somehow very therapeutic. Yep, only vaguely on topic, but what the hell, we're talking about vacuum tubes.

    • Re: (Score:1, Funny)

      by Anonymous Coward

      It's just fucking piano music. Fuck you.

      • The first time I opened it, there was no picture, the second time however, the video showed, and it indeed is a vacuum tube being manufactured by "hand".

  • by Anonymous Coward on Monday June 06, 2016 @06:40PM (#52262959)

    Call me dumb if you want, but I design ASICs for a living. How am I supposed to design a chip with these devices. When I design in CMOS silicon, I have the choice of four different polysilicon well types (P, P+, N and N+). Do these devices require several voltage rails to provide bias, in the way that the dopant provides intrinsic bias in a FET?

    I'm not old enough to have designed valve circuits, but from what I vaguely recall, you only get emission from cathodes, so with no hole mobility I don't understand quite how these things are supposed to provide complementary logic.

    • As I recall.... Out of the cobwebs..

      Where the transistor (bipolar PNP/NPN types) are usually designed with "current gain" and not voltage, vacuum tubes are more voltage driven devices where you have voltage gain. You bias a tube with voltage, by carefully adjusting the grid, almost exactly like you bias a bipolar transistor with current to get the device into the active region. Apply a little bit of varying voltage to the grid and see a large variation on the cathode plate voltage, just like varying the b

      • by serviscope_minor ( 664417 ) on Tuesday June 07, 2016 @03:51AM (#52265309) Journal

        You have to get the cathode hot enough for the electrons to want to leave and head for the plate and it takes fairly high voltages to make everything work, both of these are not good things for existing solid state devices where you want to keep the voltages and temperatures low. Doesn't seem like a good mix to me.

        That's the interesting thing: you don't. Another fun fact: once you get small enough atmospheric pressure air is essentially a quite good vacuum. The other thing is that field gradient alone can get electrons to leave without heating if it's high enough. For a high gradient you need either high voltages or high curvature. With nanoscale fabrication techniques, you can make quite extreme curvatures. Since the voltages are low, even a quite good vacuum is good enough because the electrons flying through it lack the energy to ionize air molecules.

        Look up "vacuum channel transistors".

        The best thing is, you can make them on a standard CMOS process.

    • Pretty much what you describe. Depending on the actual tube design, there may be up to (usually) 3 or 4 different bias levels. As you noted, tube circuits are all voltages, much like classic FETs. Only real difference is that the voltage values are higher, and the amplification factors / transconductance tends to be lower. (I last designed tube stuff back in the 1980's.)

    • by Agripa ( 139780 )

      I'm not old enough to have designed valve circuits, but from what I vaguely recall, you only get emission from cathodes, so with no hole mobility I don't understand quite how these things are supposed to provide complementary logic.

      They cannot but before complementary devices became available, all NPN, NMOS, and PMOS logic were common. Vacuum tubes are depletion mode devices like n-channel JFETs but there are other structures possible like beam deflection tubes.

    • by gweihir ( 88907 )

      The article is mostly BS. These new vacuum tubes are not for logic, they are for RF. A primary reason is the problems you describe. Another is that they will _not_ get as small as logic transistors anytime soon. But for RF, they are superior to silicon.

  • by Kjella ( 173770 ) on Monday June 06, 2016 @06:46PM (#52262989) Homepage

    I've no doubt we can make ten or a hundred nano-vacuum tubes atom by atom. But compared to many billions of transistors? It looks like EUV litography @ 7nm will be ready by the end of the decade, but in the 2020s I suspect we'll hardly see any progress at all.

    • by Anonymous Coward

      Vacuum tubes, by using different physics, can switch at 10 THz. It doesn't matter how many transistors you can cram into a space, if your algorithm is intrinsically serial.

      • by Anonymous Coward

        Switching speed is not the limit of digital logic. The limit is derived from the inherent capacitance and inductance of the wires and channel. Signals optimally travel at 1/10th the speed of light (freespace) in silicon, when buffers are chaines and sized optimally. In non-optimal configurations, signals trvael slower. So the fundamental limitation is not the switching speed but the longest unclocked path in the circuit, more simply known as the critical path.

        It is possible to reduce the critical path in a

  • Steam Punk (Score:5, Insightful)

    by Tablizer ( 95088 ) on Monday June 06, 2016 @06:46PM (#52262995) Journal

    Don't tell me, steam will also make a comeback.

    That's gonna be so cool: switch it on and you hear:

    Chug......chug...chug, chug, chug as puffy white smoke billows out.

    And then Microsoft will tell you, "640 gallons of water oughtta be enough for anyone!"

    • Re:Steam Punk (Score:5, Informative)

      by Anonymous Coward on Monday June 06, 2016 @06:54PM (#52263045)

      Steam never went away. Power plants that use heat (e.g., nuclear or gas) generally heat water to make steam and pass it through a turbine. Yeah, it's not the same thing as the huge piston steam engines with brass fittings that you're thinking of; but it's still steam.

      • nuclear and coal use steam. also concentrated solar power and geothermal power plants. gas and petroleum are usually burned directly in a turbine although there may be a few gas fired steam turbine plants left.

    • Not only that, you'll be able to keep warm on cold winter nights by using Steam Heat. []
  • or have they failed to miniaturize cranks yet?

  • You're off by several orders of magnitude here. Think of the size of those 1970's vacuum tubes. Now think of the size of a single CPU. Now consider how much smaller said CPU already is. On top of that, consider the billion+ transistor count in current gen CPUs. So if the vacuum tubes are only 1 million times smaller, they have a long LONG way to go to reach the billion times smaller they need to achieve to even complete with current tech!

  • Computing is going to continue gaining power even if lithography stops. As some point they are going to figure out how to entagle quantum objects without having to cool them to 3K and the widespread quantum computer will be born. Quantum computers are like an analog and digital computer combined. There are multiple answers where digital only has 2, but the number of answers are limited to a finite set, unlike analog.

    I also expect analog computing to make a reentry if for no other reason than AI. Brains are

  • by Bruce Perens ( 3872 ) <> on Monday June 06, 2016 @07:31PM (#52263243) Homepage Journal


    Just no. Nada. Not gonna happen.

    And who at Slashdot took this seriously?

    • by Khyber ( 864651 )

      Those of us with actual experience building devices with valves knew this years ago. When you can switch a tube at terahertz+ speeds, silicon looks like utter shit.

    • by Khyber ( 864651 )

      Then to boot, even at say 50nm per tube size, you've got something roughly the size of an old Pentium Pro processor, running 300x the speed of most current processors. Tubes also have the potential to be more energy efficient and the efficiency gains just JUMP as you drop in size.

  • with vacuum tubes.

    So wait: You're telling me that soon the Internet WILL BE made up of a series of tubes? []

    He was a visionary, ahead of his time. (cough, just another clueless manager, cough.)

  • I find the "consume less power" claim a but surprising, given that vacuum tubes work by heating a piece of metal to white hot until it starts flinging off electrons []. Sure, they're talking about making them very small, but the Apple A8 processor in my smartphone has 2 billion transistors []. The heat from that many tiny vacuum tubes would add up.
    • by Anonymous Coward
      Field emission (FE) (also known as field electron emission and electron field emission) is emission of electrons induced by an electrostatic field. The most common context is field emission from a solid surface into vacuum. However, field emission can take place from solid or liquid surfaces, into vacuum, air, a fluid, or any non-conducting or weakly conducting dielectric. The field-induced promotion of electrons from the valence to conduction band of sem

    • by Khyber ( 864651 )

      " given that vacuum tubes work by heating a piece of metal to white hot"

      My 1978 Fender Super Reverb 6L6 tubes barely glow red with 200 watts blowing through them at maximum volume on both channel and master, after an hour of operation. Try again.

      • Try again.

        "given that vacuum tubes work by heating a piece of metal to red hot"

        Does that make you feel better?

  • by Waffle Iron ( 339739 ) on Monday June 06, 2016 @08:15PM (#52263485)

    I find that the results from numerical computations on today's transistor-based CPUs often have an undesirable "harshness".

    Vacuum tube CPUs will hopefully yield richer, more mellow computational results.

  • My next phone will have the latest cathode ray display technology.
  • You know how Apple released the original iPad in 2010? And then they were hiring 10s of thousands of employees and spending billions on R&D without anything significant to show for it besides minor annual hardware revisions? Pretty much until Apple watch was announced in '15?

    There are many reasons why hardware lifecycles are different from software. No idea about the real story, but what is released or not released in 2 1/2 years is not much of indication of anything.

  • Will this finally make tube-based guitar amps more affordable?

    It's sad when you can buy a 150W solid-state amp with 5 DSP's that fairly convincingly models the behavior of a dozen tube amps for $300 but a 15W tube amp can still run you $1,000 easy and will be a total 1-trick pony.

    • by JustNiz ( 692889 )

      This is starting to get pretty close to those people that claim they can totally hear the difference when playing MP3s over those $20k ethernet cables.

    • by Khyber ( 864651 )

      Yea, nothing can emulate a 1978 Super Reverb. NOTHING. The hand wiring of every single component ensures natural variation in tonal quality.

      ~playing guitar for 20 years

  • Absolutely no details given on the miniaturized tubes or how they were made. The only description is this: "a million times smaller than those in use 100 years ago."

    Does anybody know how big they were 100 years ago? I have no idea. I'm guessing most people don't. Since when did "fraction of size of a vacuum tube from 1916" become a unit of length?

    Seriously, how big are they? Assuming a vacuum tube in use in 1916 was 10cm in length, I'm coming up with 100nm, which is FREAKING HUGE compared to present day

    • not to mention vacuum tubes also will hit limits where quantum effects completely dominate at about the same scale that silicon based ones will. it isn't a solution that avoids Moore's law

  • by GuB-42 ( 2483988 ) on Tuesday June 07, 2016 @12:27AM (#52264735)

    A vacuum tube is a macroscopic device. An electrode is heated, electrons shoot out and their trajectory is controlled by charged grids.
    On microchip scales, it's all about quantum physics. Electrons are wave-like, they tend to teleport through obstacles, change size as they are heated or cooled down, really weird stuff. The math probably works but I wouldn't call these things "vacuum tubes" when the very notion of everything that makes up a vacuum tube is challenged at these scales.

  • Back when I was a young CS student, my teachers used to regale me of tales when there were people with full-time jobs riding around the computer (supposedly on unicycles) with a backback full of vacuum tubes replacing them as they burned out.

    That's going to be a hellova interesting job now that their size is measured in nano-meters and there are billions of them on a chip.

    • Most tubes fail because the filament breaks, and many others wear out as the emission-enhancing oxide bakes off. Field-emission vacuum tubes lack those mechanisms, although I do wonder about the tiny electrodes eroding under heavy current flow.
  • ... humming that song from the musical "On Broadway" while ruminating on the history of technology.

    Back in the 1950s Bell Labs had the transistor as the latest and greatest new thing. General Electric was also working on miniaturized electronic devices with arrayed vacuum tubes. The G.E. idea was to build miniature vacuum tube circuits in a sealed housing that would be pumped to a vacuum to work. For repair or to modify circuits you would break the vacuum, open the housing, and work on it

Beware of Programmers who carry screwdrivers. -- Leonard Brandwein