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Power Technology

Replacing Silicon With Gallium Nitride In Chips Could Reduce Energy Use By 20% 90

Mickeycaskill writes: Cambridge Electronics Inc (CEI), formed of researchers from the Massachusetts Institute of Technology (MIT), claim semiconductors made of gallium nitride (GaN) could reduce the power consumption of data centers and consumer electronics by 20 percent by 2025. CEI has revealed a range of GaN transistors and power electronic circuits that have just one tenth of the resistance of silicon, resulting in much higher energy efficiency. The company claims to have overcome previous barriers to adoption such as safety concerns and expense through new manufacturing techniques. "Basically, we are fabricating our advanced GaN transistors and circuits in conventional silicon foundries, at the cost of silicon. The cost is the same, but the performance of the new devices is 100 times better," Cambridge Electronics researcher Bin Lu said.
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Replacing Silicon With Gallium Nitride In Chips Could Reduce Energy Use By 20%

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  • One question (Score:4, Interesting)

    by viperidaenz ( 2515578 ) on Wednesday July 29, 2015 @03:52PM (#50209197)

    What's Gallium Nitrade?

  • Denser chips (Score:4, Interesting)

    by Alain Williams ( 2972 ) <addw@phcomp.co.uk> on Wednesday July 29, 2015 @03:59PM (#50209249) Homepage

    This suggests less heat which means that chips could be packed in more densely, need smaller heat sinks. This could also remove some of the heat issues associated with multi layer chips [wikipedia.org].

    A win in many ways!

    • by x0ra ( 1249540 )
      OOTH, none of these relate to the current limitations manufacturer are hitting, which is that lithography at the current scales are becoming nearly impossible.
      • Re:Denser chips (Score:5, Informative)

        by MattskEE ( 925706 ) on Wednesday July 29, 2015 @08:30PM (#50211211)

        Gallium Nitride (GaN) isn't going to be used for digital computer, rather it is being targeted towards power conversion circuits such as computer power supplies and motor drives. For these applications gate lengths are typically of the order of 1 micron which is child's play compared to the ultra scaled digital devices.

        GaN's circuit size advantage is only partially from the reduced size of the chip, it is the fact that the GaN transistor can operate faster while producing less heat in power conversion circuits. Since the transistor produces less waste heat the heatsink is smaller. Since it can switch faster it means that the inductor and capacitor filter components can be smaller. All of this translates into much higher power per volume.

    • And then, the Jevons paradox will take care of negating those savings... ;)
    • Isn't Gallium much much more scarce than silicon? Does this increased cost justify its increased efficiency?
    • by PaulBu ( 473180 ) on Wednesday July 29, 2015 @05:38PM (#50210123) Homepage

      TFA is a bit light on details, but (having heard of GaN before), it is good at handling large voltages/currents, and they are probably talking about more efficient power supplies (saving 20%, apparently), not replacing Si in logic chips. Or maybe integrating power conversion onto processor die itself, but the latter is still made of good old CMOS. Currently, from what I've heard, a good chunk of pins on your processor are used to supply power -- if you think of it, 30W processor with 3V bias needs to get 10A of current.

      Paul B.

  • by BeerCat ( 685972 ) on Wednesday July 29, 2015 @04:00PM (#50209259) Homepage

    I remember back in the 80s that light meters in cameras used to use Silicon (SPD - Silicon Photo Diode), but then they all started using Gallium Arsenide (GASP - Gallium Arsenide Photo Diode), as it reacted faster (presumably because of the lower resistance).

    There was even talk back then about making Gallium based semi-conductors, for the same reason.

    Good to see it coming to fruition

    • I read a book a while back called "the disappearing spoon" where it discussed how earlier semiconductors used gallium, but were failure prone due to the heat (gallium has a very low melting temperature). Silicon was a godsend and once that was used, it changed semiconductors forever.

      My first thought after reading the summary was "oh no! Not this again!" But the "nitrade" may make a huge difference. Hopefully this is the case.

      • I seem to remember early transistors being made of germanium - on the row below silicon and one to the right of gallium

        • by aitikin ( 909209 )

          I seem to remember early transistors being made of germanium - on the row below silicon and one to the right of gallium

          Still are in guitar pedals, particularly vintage sounding fuzz pedals. Very vibey and not 100% reliable, so I'm glad we moved away from them for other purposes.

      • Gallium Nitride has an extremely high melting point, it is usually grown at temperatures above 600C.

      • You're referring to Germanium, which was used in the 50's.

    • What are the safety issues that the article refers to? I assume it has to do with chemicals required to manufacture, but it is unclear.
    • Are you sure it wasn't CdS and silicon, actually? It doesn't sound plausible to me that the reaction time of silicon devices would be problematic for light meters. Even for flash meters, actually.
    • Back in the 80's they would have been talking mainly about Gallium Arsenide (GaAs) which is what enabled cell phone and wifi transceivers. Now silicon is taking much of that market back from GaAs since silicon has improved to the point where it is good enough for these applications and can be cheaper and more highly integrated.

      Gallium Nitride got going in the 90's, being explored by the DoD for radar and other radio applications. In fact one of the goals was to just get better solid state drive amplifiers

    • GaAs has a better match to the visible spectrum than Si (not much IR response in GaAs due to the larger bandgap). This was valuable particularly for film cameras, as common films were not IR sensitive.

      The response speed of silicon is plenty fast. Prior to the use of silicon, cadmium sulfide and cadmium selenide (IIRC) were used in light meters, and their method of operation was much different from silicon photodiodes. CdS was used as a bulk photoresistor, and due to inherent multiplication properties was mu

      • by BeerCat ( 685972 )

        Interesting to hear more about the different kinds of photodiodes - my knowledge was far more superficial (coming from hobbyist magazines, that tended not to go into the details)

  • Hey! I don't want any artificial ingredients in my chips! Just potatoes, oil, and salt, that's it!

    • Be careful of that Sodium Chloride, it sounds pretty scary. I have also heard, that if you reduce the amount you ingest, it reduces your blood pressure. This is scary stuff!

      • Dihydrogen Monoxide kills hundreds of times more people every year than Sodium Chloride does... If you die from Sodium Chloride, to the police categorize it as assault?
        • What really keeps police busy is high school chemistry lessons. You know the one where you dissolve crystals in water, put in some electrodes and run a current through? That will get you charged with assault and battery.

        • by sconeu ( 64226 )

          I heard that Hydroxylic Acid is just as dangerous as DHMO

  • Wait, it performs 100 times better, but there's only 20% in energy savings? Um ...
    • by RingDev ( 879105 )

      I would ass-u-me that this would mean that over a period of time X, a current generation chip would process Y commands consuming N units of energy.

      The new chip would perform 2Y commands over X time while only consuming .8N units of energy.

      Or that each command execution would take 80% of the energy of a current gen chip, but that it could complete twice as many of them in the same time period, meaning a net increase of ~60% energy consumption at sustained max load.

      Tons of ways to play with the statistics on

      • by rickyb ( 898092 )
        100 times better != 100% performance improvement. 100 times better = 10000% performance improvement.
    • by nerdbert ( 71656 )

      Switching power supply efficiencies are typically in the range of 60-80% depending on load, configuration etc. Typically, slightly more than half of the "wasted" power is in the switches, and about half of that is switching the gates themselves if you're trying to go much above 5 MHz (as you go higher and higher frequency, you burn more and more energy charging/discharging the gate of the switch and your efficiency drops, which is why you don't typically see non-integrated switching power supplies above 5-1

  • I think this may be a marketing mistake. Can we get the performance boost with the new substance but continue to call the new substance "silicon"? Perhaps we could rename silicon as something else to free up the namespace? "Silicon classic" perhaps? :-)

  • It's been a while since I took electronics. Doesn't power consumption increase with lower resistance for a given voltage? These claims seem counter intuitive.
    • by Anonymous Coward

      Lower resistance means throwing less energy away as waste heat, giving you the freedom of either making your chips faster, or require less cooling.

    • Ohm's law: V=IR => I = V/R
      Power dissipated in a resister: P=VI
      Substituting for I from Ohm's law: P=V^2/R
      So for a fixed voltage, you dissipate more energy with a low resistance. This would be what you're remembering from electronics. For example if you attempt to short high tension power lines with a dry kite string, the effect will be unimpressive. On the other hand if you short them with a solid copper bar, expect to be rained with molten copper.

      However it is not the case that you're going to take a ci

    • by nerdbert ( 71656 )

      Switching power supplies are complicated, but here's a simple conceptual version.

      You've got a high voltage coming in. You've got a transistor that you turn on and off that goes to a capacitor and to your load. You pulse the voltage at the capacitor/load and turn the switch on and off to keep the voltage at the load close to what you want by varying the width of the pulse. Ideally you want that transistor to conduct with zero resistance when it's on so that you deliver current to the load with no power dissi

  • by elgol ( 1257936 ) on Wednesday July 29, 2015 @04:33PM (#50209511)

    Efficient Power Conversion (EPC) [epc-co.com]

    GaN Systems [gansystems.com]

    Transphorm [transphormusa.com]

    Panasonic [panasonic.co.jp]

    Infineon [infineon.com]

    Disclaimer: I work for one of the listed companies. We welcome new members to the GaN club!

    I apologize to the ones that I missed.

    • by Anonymous Coward

      And of those companies above, only EPC has a serious product range that you can actually buy from an electronic component distributor, based on a technology that can be considered quite mature now (they started selling them in 2009, they're at their 4/5th gen now).
      For a few months now, GaN Systems has also been offering 2 references through a distributor, but they're still the early production run kind of stuff with incomplete datasheets and cost like several dozens bucks a piece. But unlike EPC, their tech

    • Cree (the LED company) also makes high power GaN RF chips. The power and RF chip division is about to be spun off into an unnamed company in a few months.
  • by TheHawke ( 237817 ) <rchapin@NOSPam.stx.rr.com> on Wednesday July 29, 2015 @04:38PM (#50209565)

    It's also used in LED's, plus military applications like active phased array radar systems. This breakthrough will make the LED market cost plummet, plus bring the modern radar systems cost down even lower to where other gov't agencies like NOAA and even upper crust civilian markets to own the radar for their own uses.

  • Wouldn't this increase battery life in mobile devices? Data centers could all be run off of solar/wind/wave power, if we really cared about energy use.
  • Back in the seventies, working for a military contractor, we built microwave communications and countermeasures equipment using GaAs devices. Later, working for the cell phone industry in the early nineties, I seem to remember that at least some manufacturers were switching to GaAs-based radios in cell phones. It's my impression that even today they're used often for high frequency devices. Seems like the only news here is the improved method of manufacture, as the technology has been around for decades.

    • GaAs and GaN have some real advantages over silicon, but price and density has not been their strong suit. Silicon is cheap per unit of area, and is compatible with copper metallization. GaAs in particular has always been sensitive to copper contamination, hence the use of gold for most of the interconnects. GaN has very fast switching speeds while handling an order of magnitude more voltage than GaAs (~10x the breakdown for the same Ft). So for a ~100 GHz Ft silicon can handle just a volt or so (think

    • by Anonymous Coward

      GaAs is old, but still useful for RF semiconductors. Small wafers, special foundries, and higher cost are the norm.
      GaN is new(er) and holds many performance and process advantages. Higher voltage tolerance, lower resistance, better thermal conductivity, allowing transistors to be made smaller with attendant lower capacitance’s. This means much faster switching times, or higher maximum frequency and power. Higher voltage tolerant parts means the ratio between current and voltage could be closer to the

  • Where are the 100Ghz chips? fck these 20% more effecient chips, ditch silicon already, it's too slow.

  • Wasn't this known since the 1970s?

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