Why can't Moore's Law work forever?

Question

What are the limitations to this law?

Answer 1

Size and speed of the particles really. They have a finite size and speed. Silicon is the miracle element in electronics and can practically be shaped down to the atomic level with few problems, so there is still much room for innovation. However, there still eventually will be limits to the current technology we use, although we won't likely reach them anytime soon.

However, what can possibly keep Moore's law going into the future may be new blends of electronics, such as relying on the spin of electrons ("Spintronics") and such instead of their movement from point A to B.

Answer 2

An operative electronic component with less than a few hundred molecules in it would be slightly unpredictable, due to the Uncertainty Principle and possibly due to cosmic background radiation.

Five million such components are about the minimum to make a processor. Allowing for inter-component insulation, that's going to be a cube at least 200 nanometres on a side. So even if signals propagate through it at light speed, you can't run it faster than about 10^15 Hz without one half of it getting out of phase with the other half. End of Moore's Law.

Of course, attaching enough wires to a 200 nm cube to operate it usefully as a processor would be another problem.

Answer 3

Eventully we'll hit photolithography limits and since you say "forever" eventually it would require sub-atomic dimensions