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posted by janrinok on Tuesday February 06, @10:53PM   Printer-friendly

Over the past decade, one of the biggest stories in semiconductors has been a surprise eclipsing of traditional silicon—in the field of power electronics, where silicon carbide (SiC) and gallium nitride (GaN) have raced past silicon to capture multibilllion-dollar segments of the market. And as major applications fell to these upstarts, with their superior attributes, a question naturally arose. What would be the next new power semiconductor—the one whose superior capabilities would grab major market share from SiC and GaN?

Attention has focused on three candidates: gallium oxide, diamond, and aluminum nitride (AlN). All of them have remarkable attributes, as well as fundamental weaknesses that have so far precluded commercial success. Now, however, AlN's prospects have improved enormously, thanks to several recent breakthroughs, including a technological advance at Nagoya University reported at the most recent IEEE International Electron Devices Meeting, held this past December in San Francisco.

The IEDM paper describes the fabrication of a diode based on alloys of aluminum nitride capable of withstanding an electric field of 7.3 megavolts per centimeter—about twice as high as what's possible with silicon carbide or gallium nitride. Notably, the device also had very low resistance when conducting current. "This is a spectacular result," says IEEE Senior Member W. Alan Doolittle, a professor of electrical and computer engineering at Georgia Tech. "Particularly the on-resistance of this thing, which is ridiculously good." The Nagoya paper has seven coauthors, including IEEE Member Hiroshi Amano, who won a Nobel Prize in 2014 for his role in inventing the blue LED.

[...] "This is a new concept in semiconductor devices," says Jena, of the Nagoya device. The next step, he adds, is fabricating a diode that has a layer of pure AlN at the junction, rather than 95 percent AlN. A layer of AlN just 2 micrometers thick would suffice to block 3 kilovolts, according to his calculations. "This is exactly where this will go in the very near future," he says.

At Georgia Tech, Doolittle agrees that there is still room for enormous improvement by incorporating higher levels of pure AlN in future devices. For example, the breakdown electric field of the Nagoya diode, 7.3 MV/cm, is impressive, but the theoretical maximum for an AlN device is about 15. Thermal conductivity, too, would be greatly improved with more AlN. The ability to conduct heat is vitally important for a power device, and the thermal conductivity of the AlGaN alloy is mediocre—below 50 watts per meter-kelvin. Pure aluminum nitride, on the other hand, is very respectable at 320, in between GaN, at 250, and SiC, at 490.

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  • (Score: 1, Interesting) by Anonymous Coward on Wednesday February 07, @01:29AM (5 children)

    by Anonymous Coward on Wednesday February 07, @01:29AM (#1343428)

    Seems to me that high power inverters (DC-to-AC) are the big users of devices like this. If they are cheaper and/or more efficient than the present choices, we're likely to start seeing them in BEVs, big DC transmission lines and so on.

    • (Score: 2) by crafoo on Wednesday February 07, @03:00AM (2 children)

      by crafoo (6639) on Wednesday February 07, @03:00AM (#1343447)

      microwave devices too, I believe. high-power weapons radars and such

      • (Score: 2) by mhajicek on Wednesday February 07, @06:33AM

        by mhajicek (51) on Wednesday February 07, @06:33AM (#1343460)

        Motor controllers for electric vehicles.

        The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
      • (Score: 2) by Rich on Wednesday February 07, @01:28PM

        by Rich (945) on Wednesday February 07, @01:28PM (#1343506) Journal

        Not sure about microwave frequencies, I guess these GHz speeds are above the switching speed of semiconductors. Industrial RF heating, which operates in the 20-50 MHz range, might be a market. It's one of the last areas where thermionic valves are still a thing. The 3kV rating is just in the ballpark of, say, a TB4/1250 (5868) valve used in that area.

        Besides that, residential substations could be affected where they go down from medium voltages to household supply. I imagine it might not only save a lot of copper, but could also stabilize the AC waveshape (which is the reason that we have increasing power factor regulations)

    • (Score: 2) by Freeman on Wednesday February 07, @03:30PM

      by Freeman (732) on Wednesday February 07, @03:30PM (#1343519) Journal

      I look forward to the phasing in of such technology in the next decade. Wait how long did it take for nano-crystal displays to become a thing?

      Let's see here, first report I remember: [] - May 2006.

      Seth Coe-Sullivan, chief technology officer at Watertown, MA, startup QD Vision, fastens alligator clips to two edges of a transparent wafer the size of a cell-phone screen and flips a switch: a rectangle filling the center of the wafer suddenly turns from reflective silver to faint red. A lab worker turns off the room lights to heighten the effect – but this isn’t necessary. Coe-Sullivan turns a knob and the device begins glowing brilliantly.
      This is QD Vision’s first display – a monochromatic 32-by-64-pixel test bed for a technology Coe-Sullivan hopes will replace those used in today’s high-definition TVs.
      At its heart are nanoparticles called quantum dots, nanoscale semiconductor crystals.

      First introduction by Sony in 2013 with widespread adoption by 2017: []

      The first manufacturer shipping TVs of this kind was Sony in 2013 as Triluminos, Sony's trademark for the technology.[15] At the Consumer Electronics Show 2015, Samsung Electronics, LG Electronics, TCL Corporation and Sony showed QD-enhanced LED-backlighting of LCD TVs.[16][17][18] At the CES 2017, Samsung rebranded their 'SUHD' TVs as 'QLED'; later in April 2017, Samsung formed the QLED Alliance with Hisense and TCL to produce and market QD-enhanced TVs.[19][20]

      The full potential of this technology still exists in lab only:

      As of June 2016, all commercial products, such as LCD TVs branded as QLED, employ quantum dots as photo-emissive particles; electro-emissive QD-LED TVs exist in laboratories only.[7][8]

      Though, I've heard rumors that the "electro-emissive"/no need for backlight version may be close to a commercial product.

      Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
    • (Score: 2) by c0lo on Thursday February 08, @08:10AM

      by c0lo (156) on Thursday February 08, @08:10AM (#1343605) Journal

      Seems to me that high power inverters (DC-to-AC) are the big users of devices like this.

      UHV-DC power lines one can route underground/submerse w/o humongous loses? This is how Sahara may finally become a useful land.