5 ms·

Making the new silicon

51 points by user_235711 11y ago

fsdhlfkasdf 11y ago
Would this also significantly reduce the heat produced by data centers as less of the current going through the transistor is converted to heat?
- jakub_h 11y ago
  No, it wouldn't (most likely): https://en.wikipedia.org/wiki/Jevons_paradox https://en.wikipedia.org/wiki/Jevons_paradox
max-a 11y ago
Great news, but they didn't say anything about selling transistors to the public. When do you think we can expect to buy those like we do with mosfets?
- Zuph 11y ago
  You can already buy GaN FETs (although not the exact type being researched by MIT, as mentioned in the article): - http://epc-co.com/epc/Products/eGaNFETs.aspx http://epc-co.com/epc/Products/eGaNFETs.aspx - http://www.ti.com/lsds/ti/power-management/gan-overview.page http://www.ti.com/lsds/ti/power-management/gan-overview.page You could have a pile of GaN FETs on your desk tomorrow morning, if you really wanted: http://www.digikey.com/product-search/en?pv606=18&FV=fff40015%2Cfff8007d&mnonly=0&newproducts=0&ColumnSort=100001&page=1&k=&stock=1&filterAlwaysExpand=1&quantity=1&ptm=0&fid=0&pageSize=100&akamai-feo=off http://www.digikey.com/product-search/en?pv606=18&FV=fff4001...
waterlesscloud 11y ago
What happened to Gallium-Arsenide? Wasn't that going to replace silicon? Did it not pan out? Is it used in some cases? I really know nothing about the state of semiconductor materials, obviously!
- yk 11y ago
  Well Gallium-Arsenide, Indium-Phosphide and all kinds of other semi-conductors. But thing is, Silicon is well entrenched and there are work-arounds for all the different shortcomings of silicone and really a lot of experience working with Si. So the theoretical advantage of different substances where never able to overcome the momentum Si has.
  - baseballmerpeak 11y ago
    They will eventually, working from the extreme cases on in as price drops, but for the foreseeable future, Si is king.
- stephen_g 11y ago
  Most of the microwave amplifiers modules (MMICs), mixers, etc. the company I work for are built on GaAs, and we're starting to use GaN (Gallium Nitride) on one of our Ka band units (28-31GHz). The GaN parts are quite a bit more power efficient. Not exactly sure why the tech is not more widely used though. Funnily enough, most of the GaN and GaAs devices in general use are LEDs!
  - jakub_h 11y ago
    In late 1980s, it was expected that by 2000, you'd have a GaAs computer on every desktop (powered by Occam or Prolog, of course ;-)). In the end, it turned out that silicon had more life in it than was expected, while being much cheaper and easier to manufacture.
    - yakshemash 11y ago
      There was also the fact that silicon was already heavily entrenched in the industry by the time people started to tinker with the possibilities of GaAs seriously. At least that's what I understood to be the main factor after listening to Seymour Cray's talk which was posted here some time ago: https://www.youtube.com/watch?v=xW7j2ipE2Ck https://www.youtube.com/watch?v=xW7j2ipE2Ck He talks about how difficult it was to convince large suppliers to work with GaAs at about 30 minutes into the talk.
zippzom 11y ago
What is the difference between silicon and gallium nitride that makes silicon default to off when the circuit is broken and the standard GaN transistors default to on?
- TD-Linux 11y ago
  Not exactly sure what the article was going for. Maybe the importance of N-type transistors (they are useful just for being more efficient). Silicon transistors are widely known for failing in a shorted state.
- pjc50 11y ago
  I think they actually mean "depletion mode" vs "enhancement mode". It's not so much when the circuit is broken as when the gate is allowed to float. (The article doesn't even say whether they're talking about FETs or BJTs, but I presume FETs with a super-low RdsOn)
- cyanoacry 11y ago
  It's mostly a function of how the transistors are made. If a transistor is on by default, they're called "depletion-mode" transistors--this means that the channel between the two sides of the transistors normally conducts, and via the control voltage, you deplete that channel of carriers. This is set up by the "doping" of the channel, which is one of the first steps in the fab process. Transistors that are off by default are called "enhancement-mode". GaN transistors also come in enhancement-mode flavor, so I'm a little surprised by the article. You can buy them, even as a hobbyist, from EPC. [0] [0] http://epc-co.com/epc/Products/eGaNFETs/EPC2023.aspx http://epc-co.com/epc/Products/eGaNFETs/EPC2023.aspx [1] http://www.digikey.com/product-search/en?WT.z_cid=sp_917_0110_buynow&site=us&lang=en&mpart=EPC2023ENG http://www.digikey.com/product-search/en?WT.z_cid=sp_917_011...
zellyn 11y ago
"CEI’s GaN transistors have at least one-tenth the resistance of such silicon-based transistors" To be pedantic, silicon-based transistors also have at least one-tenth the resistance of silicon-based transistors.
aswanson 11y ago
Once it becomes economical, with GaN processes pick up where silicon nodes are right now, or will the whole drive have to start at a less dense node?

51 points by user_235711 11y ago

Would this also significantly reduce the heat produced by data centers as less of the current going through the transistor is converted to heat?

jakub_h 11y ago
No, it wouldn't (most likely): https://en.wikipedia.org/wiki/Jevons_paradox https://en.wikipedia.org/wiki/Jevons_paradox

max-a 11y ago

Great news, but they didn't say anything about selling transistors to the public. When do you think we can expect to buy those like we do with mosfets?

Zuph 11y ago
You can already buy GaN FETs (although not the exact type being researched by MIT, as mentioned in the article): - http://epc-co.com/epc/Products/eGaNFETs.aspx http://epc-co.com/epc/Products/eGaNFETs.aspx - http://www.ti.com/lsds/ti/power-management/gan-overview.page http://www.ti.com/lsds/ti/power-management/gan-overview.page You could have a pile of GaN FETs on your desk tomorrow morning, if you really wanted: http://www.digikey.com/product-search/en?pv606=18&FV=fff40015%2Cfff8007d&mnonly=0&newproducts=0&ColumnSort=100001&page=1&k=&stock=1&filterAlwaysExpand=1&quantity=1&ptm=0&fid=0&pageSize=100&akamai-feo=off http://www.digikey.com/product-search/en?pv606=18&FV=fff4001...

waterlesscloud 11y ago

What happened to Gallium-Arsenide? Wasn't that going to replace silicon? Did it not pan out? Is it used in some cases? I really know nothing about the state of semiconductor materials, obviously!

yk 11y ago
Well Gallium-Arsenide, Indium-Phosphide and all kinds of other semi-conductors. But thing is, Silicon is well entrenched and there are work-arounds for all the different shortcomings of silicone and really a lot of experience working with Si. So the theoretical advantage of different substances where never able to overcome the momentum Si has.
- baseballmerpeak 11y ago
  They will eventually, working from the extreme cases on in as price drops, but for the foreseeable future, Si is king.
stephen_g 11y ago
Most of the microwave amplifiers modules (MMICs), mixers, etc. the company I work for are built on GaAs, and we're starting to use GaN (Gallium Nitride) on one of our Ka band units (28-31GHz). The GaN parts are quite a bit more power efficient. Not exactly sure why the tech is not more widely used though. Funnily enough, most of the GaN and GaAs devices in general use are LEDs!
- jakub_h 11y ago
  In late 1980s, it was expected that by 2000, you'd have a GaAs computer on every desktop (powered by Occam or Prolog, of course ;-)). In the end, it turned out that silicon had more life in it than was expected, while being much cheaper and easier to manufacture.
  - yakshemash 11y ago
    There was also the fact that silicon was already heavily entrenched in the industry by the time people started to tinker with the possibilities of GaAs seriously. At least that's what I understood to be the main factor after listening to Seymour Cray's talk which was posted here some time ago: https://www.youtube.com/watch?v=xW7j2ipE2Ck https://www.youtube.com/watch?v=xW7j2ipE2Ck He talks about how difficult it was to convince large suppliers to work with GaAs at about 30 minutes into the talk.

zippzom 11y ago

What is the difference between silicon and gallium nitride that makes silicon default to off when the circuit is broken and the standard GaN transistors default to on?

TD-Linux 11y ago
Not exactly sure what the article was going for. Maybe the importance of N-type transistors (they are useful just for being more efficient). Silicon transistors are widely known for failing in a shorted state.
pjc50 11y ago
I think they actually mean "depletion mode" vs "enhancement mode". It's not so much when the circuit is broken as when the gate is allowed to float. (The article doesn't even say whether they're talking about FETs or BJTs, but I presume FETs with a super-low RdsOn)
cyanoacry 11y ago
It's mostly a function of how the transistors are made. If a transistor is on by default, they're called "depletion-mode" transistors--this means that the channel between the two sides of the transistors normally conducts, and via the control voltage, you deplete that channel of carriers. This is set up by the "doping" of the channel, which is one of the first steps in the fab process. Transistors that are off by default are called "enhancement-mode". GaN transistors also come in enhancement-mode flavor, so I'm a little surprised by the article. You can buy them, even as a hobbyist, from EPC. [0] [0] http://epc-co.com/epc/Products/eGaNFETs/EPC2023.aspx http://epc-co.com/epc/Products/eGaNFETs/EPC2023.aspx [1] http://www.digikey.com/product-search/en?WT.z_cid=sp_917_0110_buynow&site=us&lang=en&mpart=EPC2023ENG http://www.digikey.com/product-search/en?WT.z_cid=sp_917_011...

zellyn 11y ago

"CEI’s GaN transistors have at least one-tenth the resistance of such silicon-based transistors" To be pedantic, silicon-based transistors also have at least one-tenth the resistance of silicon-based transistors.

aswanson 11y ago

Once it becomes economical, with GaN processes pick up where silicon nodes are right now, or will the whole drive have to start at a less dense node?