A semiconductor is a material whose electrical conductivity falls between that of a conductor and an insulator and — crucially — can be precisely controlled.¹

Overview

Silicon is the workhorse semiconductor. By doping it with tiny amounts of other elements, makers create regions that carry charge differently (n-type and p-type), and the junctions between them behave in controllable ways. That controllability is what makes a transistor possible: a small signal can switch or modulate a larger current. Many such structures are then fabricated together on one die to form an integrated circuit.

Where it fits

Semiconductors are the physical foundation under all of digital computing: without a material you can switch on and off reliably, there are no logic gates, no CPUs, no chips at all. The decades-long ability to shrink semiconductor features is what powered Moore’s law. The same physics serves radio too — the diodes, amplifiers, and mixers in an SDR front end are semiconductor devices handling the RF before GopherTrunk decodes it.

Sources

1. Semiconductor — Wikipedia, on semiconductor materials, doping, and conductivity. ↩

See also

• Transistor
• Integrated circuit
• Logic gate
• Moore's law
• Central processing unit (CPU)
• x86