In the biz people already measure some widths as "monolayers", which refers to a single layer of atoms. Some process features have error margins of less than a monolayer -- that is, a dieletric needs to be 4 monolayers thick, and if it only has 3, the device is going to short, and if it has 5, the device will not work.

What kind of CVD/PVD process do you use to achieve those kinds of tolerances? Or is the trick to use protect/deprotect steps like in conventional chemistry?

ALD is commonly used for these ultra fine tolerances.

Atoms in a silicon crystal are about 0.54 nm apart, so we are not quite there yet.

So you're saying a 10nm structure is about ~20 atoms long? So basically proving parents point...

No, saying that we are still an order of magnitude away from dealing with individual atoms. The current slowdown is more about light than about atoms; the move to EUV lithography [1] has proved to be very challenging [2].

[1] https://en.wikipedia.org/wiki/Extreme_ultraviolet_lithograph...

[2] https://spectrum.ieee.org/semiconductors/nanotechnology/euv-...

In theory Coulomb transistors can be a single molecule. I believe single molecule transistors have been experimentally demonstrated.