That's the thing, it is not a few atoms wide. Ask google, you'll learn something. You cannot make a transistor gate of only 5 or 10 atoms, due to quantum tunneling, but I mean, without the fancy quantum name, it just means that, there are probabilities electrons still get the energy to make the jump when we don't want them to. The gate's size is not two nanometers. It's around 40nm. Or bigger.