Computer chips are at the heart of the modern technology revolution. But what are they made of and how are they made? They are made primarily of transistors, which act as electrical switches in digital circuits, and metal wires. The most significant type of transistor, from an economic perspective, is the complementary metal oxide semiconductor (CMOS) transistor. This is a three-terminal device consisting of a gate (metal), a source, and a drain. The gate is an electrical switch that controls the flow of electrons from the source to the drain. Applying a voltage turns "on" the gate, which directs an electric field across a thin silicon dioxide film, causing the semiconductor material to become conductive and thereby allowing electrons to flow. If the gate voltage is turned "off," the electrons go away. Transistors being "on" or "off" correspond to the binary "1" and "0."

So how...