Event

The semiconductor era

A material purified further than anything else made, and an industry that reorganised the world economy around it.

From the transistor in 1947 and the integrated circuit in 1958, electronics moved from vacuum tubes to solid-state devices, and one material became the substrate of nearly all of it.

Silicon was not the obvious choice and was not the best semiconductor available. Germanium has higher carrier mobility and was used first. Silicon won on a property that has nothing to do with semiconduction: it forms a stable, adherent, insulating native oxide, which is what makes the planar process possible — the oxide masks the surface during doping and then stays as the insulator. Germanium's oxide is soluble in water and useless.

That is the period's lesson in miniature. The material that wins is rarely the one that is best at the thing it is named for.

History

The point-contact transistor at Bell Labs in 1947, the junction transistor shortly after, and the integrated circuit independently at Texas Instruments and Fairchild in 1958 and 1959. The planar process, which is what made integrated circuits manufacturable rather than merely possible, follows in 1959.

The purity requirement escalated continuously. Semiconductor-grade silicon is refined to around eleven nines — one impurity atom in a hundred billion — which is a purity no other material is produced at in bulk, and it is achieved by the Czochralski process pulling a single crystal from the melt.

Gordon Moore's 1965 observation about transistor counts became a planning target the industry then organised itself to meet for half a century, which is an unusual thing for an empirical trend to become.

Economic significance

The industry has the deepest and most concentrated supply chain in the world economy. Leading-edge fabrication happens in a handful of facilities; the lithography machines at the smallest nodes come from one supplier; and a shortage of unremarkable components stopped vehicle assembly lines worldwide in 2021.

It is also where the widest range of elements is used in the smallest quantities. A modern device draws on a substantial fraction of the stable elements, many in milligrams, most with no substitute — which makes criticality a question of irreplaceability rather than of tonnage.

Medium confidence Weak evidence

How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.

How this connects

Where a connection has been confirmed by an outside reference, that reference is named beside it.

involved

Silicon — element · and it won not on being the best semiconductor but on forming a stable insulating native oxide
Germanium — element · first, and displaced — its oxide dissolves in water, which the planar process cannot tolerate
Transistor — object · the device the whole period is about
Czochralski process — process · pulling a single crystal from the melt, which is how the purity and the absence of grain boundaries are achieved together
Electronics manufacture — industry · and the supply chain it produced is the deepest and most concentrated in the world economy
Gallium arsenide — compound · where silicon's indirect band gap is the limit — radio frequency and optoelectronics
Gallium nitride — compound · and it is the part of it that arrived late — red and green LEDs existed from the 1960s, and lighting waited thirty years for blue
Smartphone — object · the object the whole period arrives at, and the one that put roughly sixty elements into a pocket

Sources

Material World
Our own writing

Where it comes from, and what it becomes

Follow The semiconductor era back to what it starts as, and forward into what it becomes. Each step is a documented one — a real route material takes, not a chain of inference.

Upstream — what it comes from

The semiconductor era → involved (and it won not on being the best semiconductor but on forming a stable insulating native oxide) → Silicon → is produced by (carbothermic reduction of silica with coke in a submerged arc furnace, which is smelting in the strict sense even though no ore is involved) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → Air separation → takes as input (the feedstock, and an unusual one in being free, unlimited and available anywhere — the cost is entirely the energy to liquefy it) → Air
The semiconductor era → involved (where silicon's indirect band gap is the limit — radio frequency and optoelectronics) → Gallium arsenide → is produced by (grown as a boule and sliced, though it is harder to keep stoichiometric than silicon because the arsenic evaporates) → Czochralski process → takes as input (charged to the crucible already refined; the process changes its arrangement and its purity, not its identity) → Silicon → is produced by (carbothermic reduction of silica with coke in a submerged arc furnace, which is smelting in the strict sense even though no ore is involved) → Smelting → takes as input (roasted to drive off sulfur, then reduced to copper) → Chalcopyrite
The semiconductor era → involved (pulling a single crystal from the melt, which is how the purity and the absence of grain boundaries are achieved together) → Czochralski process → takes as input (charged to the crucible already refined; the process changes its arrangement and its purity, not its identity) → Silicon → is produced by (carbothermic reduction of silica with coke in a submerged arc furnace, which is smelting in the strict sense even though no ore is involved) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → Air separation
The semiconductor era → involved (the device the whole period is about) → Transistor → is made of (the substrate, purified to around eleven nines — a purity nothing else is produced at in bulk) → Silicon → is produced by (carbothermic reduction of silica with coke in a submerged arc furnace, which is smelting in the strict sense even though no ore is involved) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → Air separation
The semiconductor era → involved (and the supply chain it produced is the deepest and most concentrated in the world economy) → Electronics manufacture → uses (interconnect and every circuit board track) → Copper → is produced by (as blister copper, refined electrolytically afterwards) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → Air separation
The semiconductor era → involved (and it is the part of it that arrived late — red and green LEDs existed from the 1960s, and lighting waited thirty years for blue) → Gallium nitride → is sourced from (produced overwhelmingly in China, which introduced export controls in 2023 — a vulnerability that comes from the metal being somebody else's by-product rather than from any scarcity) → Gallium → is sourced from (as a by-product of the Bayer process) → Bauxite → is sourced from (the residue of prolonged tropical weathering, which strips the silica and alkalis out of an aluminosilicate rock and leaves the aluminium behind — basalt is one common parent among several) → Basalt → is composed of (an early-crystallising constituent of basaltic magma) → Olivine

These are the most distinct paths back. The semiconductor era can be traced through others besides.