A new way to extend Moore’s law

ALL good things come to an end. Moore’s law—the observation that the number of transistors that can be crammed onto a chip of a given size doubles every two years—has built the modern, computerised world. But as transistors get smaller, making them smaller still gets harder. In recent years Moore’s law has begun to slow.

For all the fearsome complexity of computer chips, their basic components are simple. Transistors are nothing more than switches. To turn one on, a voltage is applied to part of it called a gate. This allows electrical current to flow through a channel between the transistor’s input and output. As transistors shrink, though, insulation breaks down and the current applying the voltage tends to leak away, reducing the gate’s ability to control the channel. One reason for this is a phenomenon called quantum tunnelling, in which the uncertainty of an electron’s position means it is sometimes found in another part of the transistor without having physically crossed there.