FWIW, the active channel volume is much more than a dozen atoms in a modern FinFET process. For a ~5nm process, there might be only a few dozen atoms across th

FWIW, the active channel volume is much more than a dozen atoms in a modern FinFET process. For a ~5nm process, there might be only a few dozen atoms across the width of the fin, but the other dimensions are much larger, for a total of probably somewhere around hundreds of thousands of atoms per channel. see e.g. https://fuse.wikichip.org/news/2408/tsmc-7nm-hd-and-hp-cells-2nd-gen-7nm-and-the-snapdragon-855-dtco/ https://fuse.wikichip.org/news/2408/tsmc-7nm-hd-and-hp-cells... and other wikichip articles for some dimension info. but regardless, modern semiconductor manufacturing processes are incredible. the much-too-brief summary is that they shine very precise patterns of light on the silicon using very high frequency light to activate photoresist, and then etching away the silicon that isn't protected by the photoresist. this doesn't actually produce features as small as the fins, so there are a lot of tricky techniques, like doing this patterning + etching once, then growing a layer of some other material on top, then etching again to leave only the very narrow sidewalls that grew around the original feature, then etching again using the sidewalls as the pattern. https://en.wikipedia.org/wiki/Spacer_patterning https://en.wikipedia.org/wiki/Spacer_patterning it really is amazing - reliably writing tiny structures on stones with light.