Material · General Industry
Semiconductor
A material whose electrical conductivity sits between that of a conductor and an insulator, and can be controlled by doping, temperature, light or an applied electric field.
That controllability is precisely what makes switching and amplifying devices possible.
- Type
- Material
- Domain
- General Industry, Device physics
Notes
The word doubles as the name of the whole industry, so context decides whether it means a material or a market.
Overview
A semiconductor is a material whose ability to conduct electricity lies between that of a metal and an insulator and can be changed deliberately, by adding tiny amounts of impurity, applying a voltage or shining light on it. Silicon is by far the most widely used, followed by compound materials such as gallium arsenide, gallium nitride and silicon carbide. The same word is also shorthand for the devices made from these materials and for the industry that makes them.
How it works
Electrons in a solid can only take certain ranges of energy, called bands. In a semiconductor the gap between the filled band and the next empty one, the band gap, is small enough that some electrons can be lifted across by heat or light, but pure material at room temperature still conducts poorly. Unlike a metal, a semiconductor conducts better as it gets hotter.
Doping is what makes the material useful. Adding a controlled trace of phosphorus or arsenic to silicon supplies spare electrons (n-type); adding boron creates missing electrons, or holes, that also carry current (p-type). Where n-type and p-type regions meet, a junction forms that lets current pass one way only, the basis of diodes. A transistor uses junctions, or a voltage on a gate, to switch or amplify current in a small region, and an integrated circuit packs huge numbers of these regions into one crystal.
The choice of material follows the job. Wide band gap materials such as silicon carbide and gallium nitride can operate at higher voltages and temperatures than silicon, so they suit power electronics; gallium arsenide is used in laser diodes, solar cells and microwave-frequency circuits.
Examples
- Silicon CMOS logic and memory, the basis of most electronic circuits.
- Silicon carbide and gallium nitride transistors in power electronics for electric vehicles, renewable energy inverters and power adapters.
- Gallium nitride in LEDs and in radio frequency power amplifiers.
- Gallium arsenide in laser diodes, solar cells and microwave-frequency integrated circuits.
- Germanium, used in the first transistors and today added to silicon in parts of advanced transistors to improve hole mobility.
Why it matters
The material decides which fabs, process steps and equipment a product needs, which is why device engineers, process engineers and TCAD specialists work from its physics, and why design kits carry device models derived from it. Investors, policy makers and analysts mostly use the word in its industry sense.
In the chip lifecycle, material choice comes first, during technology definition and process development; everything later, from the transistor models designers simulate with to the reliability limits in a datasheet, follows from it.
It matters most to: Device Engineer, Materials Research Scientist, Process Integration Engineer, TCAD Engineer
Common confusions
- Not the same as the semiconductor industry
- "Semiconductor" names both a class of material and the global business of designing and making chips, so a sentence about semiconductor growth is usually about the market, not the physics.
- Not the same as a poor conductor
- What makes a semiconductor valuable is not middling conductivity but control: its conductivity can be switched or tuned in tiny regions by doping, voltage or light, which a metal or an insulator cannot do.
Key figures
- US$630.5 billion Global semiconductor sales in 2024, as revised by World Semiconductor Trade Statistics (WSTS) and reported by the Semiconductor Industry Association; the figure first announced was US$627.6 billion. (Source: Global Semiconductor Sales Increase 19.1% in 2024; Double-Digit Growth Projected in 2025 (press release, 7 February 2025, updated 3 March 2025), 2026-10-22)
Sources
- Wide Bandgap Semiconductors for Power Electronics (Quadrennial Technology Review 2015, technology assessment) (opens in a new tab), US Department of Energy, 2026-10-22
- Global Semiconductor Sales Increase 19.1% in 2024; Double-Digit Growth Projected in 2025 (press release, 7 February 2025, updated 3 March 2025) (opens in a new tab), Semiconductor Industry Association, 2026-10-22
- Semiconductor (Wikipedia) (opens in a new tab), Wikimedia Foundation, 2026-10-22
- Silicon (Wikipedia) (opens in a new tab), Wikimedia Foundation, 2026-10-22
Related terms
Part of the General Industry glossary, with every term in the topic and the lifecycles, tools and standards that use them.
Where it appears on the Hub
Used on 860 pages of the Hub. In each group, the pages that mention it most come first.
Lifecycle stages and gates
Roles
Suggest an improvement
Suggest an improvement to this entry
A clearer definition, an example, a correction or a source an editor can check. Editors review every suggestion before the entry changes.
Last reviewed . Written by The Semiconductor Hub editorial team. The full glossary