4 ms·

How close are we to the limits here? What is the smallest technology we can get to before physics gets in the way?

by dom96 1y ago

thechao 1y ago
This is effective feature size and has little to do with actual geometry. Transistor size has barely budged in the last 10–15 years. The limitation is electrical, and it's not clear where that limit is. The smallest gate was built with an AFM out ~7 atoms; that's about 8 orders of magnitude smaller than a transistor, rn, and upwards of 9 than a stdcell. There's a LOT of room; we just don't know a good path to get to there.
- mrb 1y ago
  "The smallest gate was built with an AFM out ~7 atoms; that's about 8 orders of magnitude smaller than a transistor" I was thrown off by your statement, so here are some numbers: a modern chip like Nvidia's GH100 manufactured at a 5 nm process is 80 billion gates in 814 mm². That means a gate is 100 nm wide which is the width of 500 silicon atoms. On a 2D area that's 250k atoms. I don't know the thickness but assuming it's also 500 atoms then a gate has a volume of 125 million atoms. So I guess you get your "8 orders of magnitude" difference if you compare the three-dimensional volume (7 atoms vs 125 million). But on one dimension it's only 2 orders of magnitude (7 atoms vs 500). And the semiconductor industry measures progress on one dimension so to me the "2 orders of magnitude" seems the more relevant comparison to make.
  - ZenoArrow 1y ago
    You're missing the key point, which is that the size referenced as the semiconductor manufacturing node is no longer an accurate description of the true transistor size, it's more of a marketing term. Even if it's possible to build transistors that are 1.4nm in size (or smaller), that is not what "1.4nm" means in the context of this announcement. I get that this can be confusing, it's just a case of smoke and mirrors because Moore's Law is already dead and semiconductor manufacturers don't want to spook investors. The performance gains are still real, but the reasons for getting them are no longer as simple as shrinking transistor size. As for the true physical limits of transistor sizes, there are problems like quantum tunnelling that we aren't likely to overcome, so even if you can build a gate with 7 atoms, that doesn't mean it'll work effectively. Also note that "gate" does not necessarily mean "transistor".
    - timschmidt 1y ago
      > Moore's law is dead People have said this for decades. Jim Keller believes otherwise and brought receipts: https://www.youtube.com/watch?v=oIG9ztQw2Gc https://www.youtube.com/watch?v=oIG9ztQw2Gc
      - SlowTao 1y ago
        Personally I wouldn't argue Moore's law is dead but I do wonder about the cost per chip. WE can still push smaller for a lot longer but the costs are starting to creep up a bit. I am not too worried though because adjusted for inflation, we are still saying a lot less for this tech than we were in pre-2000's tech. Economy of scale used to drop prices, complexity of manufacturing will slowly increase them again.
        timschmidt 1y ago
        Similar concerns were expressed around the development of VLSI tooling in the '70s. We've been on this curve for a long time. I can speak with some experience that manufacturing of steel and wood products increases similarly in cost and complexity with scale. Beasts like these exist: https://en.wikipedia.org/wiki/Heavy_Press_Program https://en.wikipedia.org/wiki/Heavy_Press_Program As long as the scale of production is increasing, additional investments will be warranted.
        SlowTao 1y ago
        That is very fair. We won't know when things finally tip over into a new state until it is in the rear view mirror.
    - mrb 1y ago
      I know and acknowledged it: GH100 gates are 100nm wide despite the "5nm" process. We all know about this discrepancy. "Moore's Law is already dead" That's clearly false, have a quick look at this chart: https://semiconductor.substack.com/p/the-relentless-pursuit-of-moores https://semiconductor.substack.com/p/the-relentless-pursuit-...
- lossolo 1y ago
  So, it's more of an engineering problem than a physical one? I read somewhere a while ago about strange quantum effects activating at these scales too. What's the current state beyond 1.4 nm with our current knowledge?
  - godelski 1y ago
    Yes. But also what you read is correct too. There are quantum effects that need be accounted for at these levels (have been for quite some time). Both things can be true.

How close are we to the limits here? What is the smallest technology we can get to before physics gets in the way?

by dom96 1y ago

How close are we to the limits here? What is the smallest technology we can get to before physics gets in the way?

This is effective feature size and has little to do with actual geometry. Transistor size has barely budged in the last 10–15 years. The limitation is electrical, and it's not clear where that limit is. The smallest gate was built with an AFM out ~7 atoms; that's about 8 orders of magnitude smaller than a transistor, rn, and upwards of 9 than a stdcell. There's a LOT of room; we just don't know a good path to get to there.

mrb 1y ago
"The smallest gate was built with an AFM out ~7 atoms; that's about 8 orders of magnitude smaller than a transistor" I was thrown off by your statement, so here are some numbers: a modern chip like Nvidia's GH100 manufactured at a 5 nm process is 80 billion gates in 814 mm². That means a gate is 100 nm wide which is the width of 500 silicon atoms. On a 2D area that's 250k atoms. I don't know the thickness but assuming it's also 500 atoms then a gate has a volume of 125 million atoms. So I guess you get your "8 orders of magnitude" difference if you compare the three-dimensional volume (7 atoms vs 125 million). But on one dimension it's only 2 orders of magnitude (7 atoms vs 500). And the semiconductor industry measures progress on one dimension so to me the "2 orders of magnitude" seems the more relevant comparison to make.
- ZenoArrow 1y ago
  You're missing the key point, which is that the size referenced as the semiconductor manufacturing node is no longer an accurate description of the true transistor size, it's more of a marketing term. Even if it's possible to build transistors that are 1.4nm in size (or smaller), that is not what "1.4nm" means in the context of this announcement. I get that this can be confusing, it's just a case of smoke and mirrors because Moore's Law is already dead and semiconductor manufacturers don't want to spook investors. The performance gains are still real, but the reasons for getting them are no longer as simple as shrinking transistor size. As for the true physical limits of transistor sizes, there are problems like quantum tunnelling that we aren't likely to overcome, so even if you can build a gate with 7 atoms, that doesn't mean it'll work effectively. Also note that "gate" does not necessarily mean "transistor".
  - timschmidt 1y ago
    > Moore's law is dead People have said this for decades. Jim Keller believes otherwise and brought receipts: https://www.youtube.com/watch?v=oIG9ztQw2Gc https://www.youtube.com/watch?v=oIG9ztQw2Gc
    - SlowTao 1y ago
      Personally I wouldn't argue Moore's law is dead but I do wonder about the cost per chip. WE can still push smaller for a lot longer but the costs are starting to creep up a bit. I am not too worried though because adjusted for inflation, we are still saying a lot less for this tech than we were in pre-2000's tech. Economy of scale used to drop prices, complexity of manufacturing will slowly increase them again.
      - timschmidt 1y ago
        Similar concerns were expressed around the development of VLSI tooling in the '70s. We've been on this curve for a long time. I can speak with some experience that manufacturing of steel and wood products increases similarly in cost and complexity with scale. Beasts like these exist: https://en.wikipedia.org/wiki/Heavy_Press_Program https://en.wikipedia.org/wiki/Heavy_Press_Program As long as the scale of production is increasing, additional investments will be warranted.
        SlowTao 1y ago
        That is very fair. We won't know when things finally tip over into a new state until it is in the rear view mirror.
  - mrb 1y ago
    I know and acknowledged it: GH100 gates are 100nm wide despite the "5nm" process. We all know about this discrepancy. "Moore's Law is already dead" That's clearly false, have a quick look at this chart: https://semiconductor.substack.com/p/the-relentless-pursuit-of-moores https://semiconductor.substack.com/p/the-relentless-pursuit-...
lossolo 1y ago
So, it's more of an engineering problem than a physical one? I read somewhere a while ago about strange quantum effects activating at these scales too. What's the current state beyond 1.4 nm with our current knowledge?
- godelski 1y ago
  Yes. But also what you read is correct too. There are quantum effects that need be accounted for at these levels (have been for quite some time). Both things can be true.