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It's odd that the presentation doesn't discuss alternatives to using silicon. Ultimately, this is akin to saying that there are limits on how small a vacuum tub

It's odd that the presentation doesn't discuss alternatives to using silicon. Ultimately, this is akin to saying that there are limits on how small a vacuum tube we can make. We already know of a number of other potential computing platforms such as graphene, photonics, memristors, and so on. These things have already been discovered, and they have been shown to work in the lab. It's really just a matter of putting the effort into producing these technologies at scale. Another interesting aspect of moving to a more efficient substrate would be that power requirements for the devices will also lower as per Koomey's law https://en.wikipedia.org/wiki/Koomey%27s_law https://en.wikipedia.org/wiki/Koomey%27s_law

rrss 7y ago
> It's odd that the presentation doesn't discuss alternatives to using silicon. You must have missed slide 41, which has a "beyond silicon" bullet.
- yogthos 7y ago
  ah appears that I did
toasterlovin 7y ago
That we are exploring other computing substrates does not mean that those substrates will be economical or practical to use. They either will be or they won't (a determination which is ultimately dependent on the laws of physics). Our exploration of other substrates is a necessary but insufficient precondition to actually putting other computing substrates into production.
- yogthos 7y ago
  It's kind of silly to assume that what we have now can't be improved significantly. We've only been doing this for a very short time in the grand scheme of things. We're certainly nowhere close to hitting any limitations when it comes to the laws of physics here.
  - toasterlovin 7y ago
    We just won't know until we get there. We have hit fundamental limits of physics for other technologies. Planes don't really go any faster today than they did 40 years ago. Cars can go faster than they did 40 years ago, but they don't in practice. We don't have flying cars. Etc. I'm not saying that none of these other computing substrates won't work, just pointing out that the simple fact that we are exploring them does not mean that they will. Technological progress is neither guaranteed nor automatic.
    - yogthos 7y ago
      I mean yes we literally don't know right now. I'm just saying given where our civilization is at, I think it's pretty safe to assume that we have a lot of room to grow here. Once we've done computing for a thousand years or so we'll be looking back at this the way we look at cavemen banging rocks together.
      - toasterlovin 7y ago
        Seems like a decent probability outcome to me. But it also seems like a decent probability outcome that we hit the end of the line of what’s feasible with silicon lithography in the next couple of decades and computing substrate progress basically stalls out for decades or longer until some other breakthrough happens. A parallel would be the stall in progress on personal automobiles until lithium ion batteries made electrification possible in the last decade.
        yogthos 7y ago
        Agree completely.
brennanpeterson 7y ago
Well...no. what it says is there are limits on how small of wires we can make, and how small of layers make a material functional (about 5). Wires can't get smaller without compromising RC (and thus speed). Quite horrifically: this is way more an issue than the transistor. Graphene and photonics don't help this. At all. It isn't a matter of how small a tube. You physically need 5nm to insulate, and 5nm for a functional material. So a 5nm device with a 5nm spacer and a 5nm space to the next device is about it. The smallest pitch of any physical device is 20nm. The critical pitches in wafer are about 30nm and 40nm, so in an ideal world, we can reach 3x, ever. It doesn't matter which material you choose. And yeah, you can stack up, but not in quite the way you dream, and thermal and processing issues make this hard in most domains. When I build, I deposit at temperatures, which affect underlying layers. So stacking doesn't quite work as you might expect. Again, real materials Ina real flow are actually different, and not in a trivial 'just make it work' reducible fashion. Memristors may not really exist, and are useful in the context of high speed memory. That has real physical challenges. And people.have spent billions for decades on this problem. Anyway, this is missing some background, but the presentation is great.
- yogthos 7y ago
  We already know you can use individual atoms as transistors [1]. So, clearly we can go a lot smaller than 5mm here. Obviously there are challenges in scaling these new substrates up to create useful chips, and creating the infrastructure to put them into mass production. My point is that we know this is possible, and an inflection point will come where investing in these new substrates starts being more lucrative than trying to squeeze more out of silicon. [1] https://www.sciencedaily.com/releases/2018/08/180816101939.htm https://www.sciencedaily.com/releases/2018/08/180816101939.h...

rrss 7y ago

> It's odd that the presentation doesn't discuss alternatives to using silicon. You must have missed slide 41, which has a "beyond silicon" bullet.

yogthos 7y ago
ah appears that I did

toasterlovin 7y ago

That we are exploring other computing substrates does not mean that those substrates will be economical or practical to use. They either will be or they won't (a determination which is ultimately dependent on the laws of physics). Our exploration of other substrates is a necessary but insufficient precondition to actually putting other computing substrates into production.

yogthos 7y ago
It's kind of silly to assume that what we have now can't be improved significantly. We've only been doing this for a very short time in the grand scheme of things. We're certainly nowhere close to hitting any limitations when it comes to the laws of physics here.
- toasterlovin 7y ago
  We just won't know until we get there. We have hit fundamental limits of physics for other technologies. Planes don't really go any faster today than they did 40 years ago. Cars can go faster than they did 40 years ago, but they don't in practice. We don't have flying cars. Etc. I'm not saying that none of these other computing substrates won't work, just pointing out that the simple fact that we are exploring them does not mean that they will. Technological progress is neither guaranteed nor automatic.
  - yogthos 7y ago
    I mean yes we literally don't know right now. I'm just saying given where our civilization is at, I think it's pretty safe to assume that we have a lot of room to grow here. Once we've done computing for a thousand years or so we'll be looking back at this the way we look at cavemen banging rocks together.
    - toasterlovin 7y ago
      Seems like a decent probability outcome to me. But it also seems like a decent probability outcome that we hit the end of the line of what’s feasible with silicon lithography in the next couple of decades and computing substrate progress basically stalls out for decades or longer until some other breakthrough happens. A parallel would be the stall in progress on personal automobiles until lithium ion batteries made electrification possible in the last decade.
      - yogthos 7y ago
        Agree completely.

brennanpeterson 7y ago

Well...no. what it says is there are limits on how small of wires we can make, and how small of layers make a material functional (about 5). Wires can't get smaller without compromising RC (and thus speed). Quite horrifically: this is way more an issue than the transistor. Graphene and photonics don't help this. At all. It isn't a matter of how small a tube. You physically need 5nm to insulate, and 5nm for a functional material. So a 5nm device with a 5nm spacer and a 5nm space to the next device is about it. The smallest pitch of any physical device is 20nm. The critical pitches in wafer are about 30nm and 40nm, so in an ideal world, we can reach 3x, ever. It doesn't matter which material you choose. And yeah, you can stack up, but not in quite the way you dream, and thermal and processing issues make this hard in most domains. When I build, I deposit at temperatures, which affect underlying layers. So stacking doesn't quite work as you might expect. Again, real materials Ina real flow are actually different, and not in a trivial 'just make it work' reducible fashion. Memristors may not really exist, and are useful in the context of high speed memory. That has real physical challenges. And people.have spent billions for decades on this problem. Anyway, this is missing some background, but the presentation is great.

yogthos 7y ago
We already know you can use individual atoms as transistors [1]. So, clearly we can go a lot smaller than 5mm here. Obviously there are challenges in scaling these new substrates up to create useful chips, and creating the infrastructure to put them into mass production. My point is that we know this is possible, and an inflection point will come where investing in these new substrates starts being more lucrative than trying to squeeze more out of silicon. [1] https://www.sciencedaily.com/releases/2018/08/180816101939.htm https://www.sciencedaily.com/releases/2018/08/180816101939.h...