In 1975 electronics pioneer Gordon Moore famously predicted that the complexity of integrated-circuit chips would double every two years. Manufacturing advances would allow the chip’s transistors to shrink and shrink, so electrical signals would have to travel less distance to process information. To the electronics industry and to consumers, Moore’s Law, as it became known, meant computerized devices would relentlessly become smaller, faster and cheaper. Thanks to ceaseless innovation in semiconductor design and fabrication, chips have followed remarkably close to that trajectory for 35 years.
Engineers knew, however, they would hit a wall at some point. Transistors would become only tens of atoms thick. At that scale, basic laws of physics would impose limits. Even before the wall was hit, two practical problems were likely to arise. Placing transistors so small and close together while still getting a high yield—usable chips versus defective ones—could become overly expensive. And the heat generated by the thicket of transistors switching on and off could climb enough to start cooking the elements themselves.