One of the images has "15 rows of Si atoms".
Is there a limit to how small things can go? A single atom?
Is there a physical/molecular limit to Moore's Law?
Is there a limit to how small things can go? A single atom?
Is there a physical/molecular limit to Moore's Law?
Once you make the gate of a transistor small/thin enough, quantum effects take over. Electrons will randomly teleport into and through the gate causing the transistor to conduct when it shouldn't. I don't have numbers to hand, but it's on the order of a few atoms wide. There's really nothing that can be done about it either, as far as we know. Electrons just aren't physical objects at this scale, you can't simply exclude them from any given volume of space. The electron wave function will simply just appear wherever it wants (within the electron probability cloud). The only way to stop it is to make your insulating junction thicker than the probability cloud.
I don't know which is more ridiculous, the fact that reality works like this, or, that a species of apes was able to figure this out.
Even if there isn’t, the way it seems all based on the uneven flow of state over spacetime is deeply fascinating for someone who studies computing.
And frankly, the sheer insanity of quantum teleportation is why I don't buy any argument that faster than light travel is impossible. Not because "teleportation", but because every time we think we understand the rules of the universe, it laughs in our face. The universe is wacky beyond our wildest dreams.
It doesn't mean "we believe reality works this way". It means "at extremely small scale, probabilistic models from QM best predict the behavior of electrons".
It's like the speed of light being a constant, or the Planck length being the smallest that can be subject to standard physics.
Quantum computing, which is a complete change in the actual physical model of computing, appears to be the only alternative.
there is a clear way forward with wafer stacking instead of shrinking layouts but so far we only have amd v-cache style asymmetric designs with memory stacked on top of compute. for a fully connected stack that acts like a single chip you need insane precision to align the wafers and a way to remove heat from the middle so the chips dont fry themselves.
if someone finds a way to stack cpu cores without thermal issues that will be a real revolution. huawei might be close with their logic folding but nobody knows if it really works and what the heat problems are like.
... inside a silicon crystal.
You can keep the electrons into as small a volume as you want, but you need something there forcing them, and doped silicon will only force them so much.
In fact, those transistors are smaller than what a silicon crystal can do, and the electrons are only held there because they are made of more materials than only silicon.
Yes, single-atom manipulation has already been demonstrated:
* https://en.wikipedia.org/wiki/IBM_(atoms)
Can you make transistors using that technique? Can you smaller?
And you could write nice sci-fi about subatomic transistors, but forget making them in this reality.
Beyond that, engineering a quark-gluon plasma as a processor? I'd watch that Star Trek episode. (we might fantasize about stuff like that but we're roughly monkeys smashing rocks together in a cave vs. building an iPhone sort of gap away from that kind of thing unless somebody has a really good idea)
I always thought the true limit was the Planck length against which an atom is giant. There's a whole zoo of sub-atomic particles but I don't think we know how (or if) we can apply those for practical computing.
You also have quantum computing, which I think can/does use subatomic particles? Not sure about that one
The issue with “just” photons and electrons is that you need something else to force them to behave like you want. And photons are large and non-interacting, really the opposite of what you want for computing. Great for communications of course.
what matters is the size of the pumbing
Another type of quantum computer uses qubits consisting of "quantum circuits" which are actually huge macroscopic constructions (> 1mm).
>We got pretty damn close in the vacuum tube era
Uh, what?
There's only so many fundamental interactions in the Universe. Computing requires you to be able to distinguish two states and our current methodology is built around some sort of black box three input machine that can output either state, a switch.
That switch is the part that cannot be scaled down infinitely. The reality we are familiar with doesn't exist at atomic scales. "Things" don't even have properly defined boundaries at a certain level, and thermal noise is a huge issue.
IMO a much more direct limiter of our current computing capability is lack of manufacturing ability, and heat. We were lucky that transistors were so amenable to lithography as a concept, that they work so well in 2D and as a surface feature, as that is what drove our advances the past 100 years and enabled computing to be such a normal thing. The combination of a "Solid state" effect, the electric force having very convenient properties, and lithography being so amenable to scaling things in various directions is how we got here.
But lithography doesn't scale into 3D. We've been hacking around that by doing more layers but that scales awfully, has very strict limitations, and makes the heat problem infinitely worse, to the point of making it impossible to work around.
If we could assemble things atom by atom exactly how we want, we could vastly improve our theory and practice, and build really intricate processor chunks with effective cooling channels or something, and computing would scale so much more. Maybe. Maybe some other problem would suddenly start dominating in that world.
Biology literally is nanotechnology, but it takes massive tradeoffs in exchange. It might never be possible to manufacture, at scale, stuff atom by atom. The Universe doesn't promise us infinite progress in technology. Quite the opposite.
Wait, what? How does this work in principle for storage? You can store electrons but you're saying you can store photons too?