Semiconductor glossary

Fundamentals

Semiconductor

A material whose ability to conduct electricity sits between that of a conductor, such as copper, and an insulator, such as glass. Because that conductivity can be controlled precisely, semiconductors are used to build the switches at the heart of every modern electronic device. In everyday industry use, "semiconductors" also refers to the chips made from those materials and to the industry that designs and manufactures them.

See alsoTransistorIntegrated circuit (IC)Compound semiconductor

Transistor

A semiconductor switch that turns a current on or off, or amplifies it. Transistors are the basic building block of digital logic: billions of them, patterned onto a single piece of silicon, make up a modern processor.

See alsoIntegrated circuit (IC)Node

Integrated circuit (IC)

A complete electronic circuit — transistors, interconnections and other components — fabricated together on one small piece of semiconductor material. "Integrated circuit", "microchip" and "chip" are generally used interchangeably.

See alsoChipDieTransistor

Chip

The everyday word for an integrated circuit: a single packaged semiconductor device that performs a function such as processing, memory, sensing, power conversion or radio communication.

See alsoIntegrated circuit (IC)PackagingDie

Manufacturing

Wafer

A thin, highly polished disc of semiconductor material — most often silicon — on which many chips are built at the same time. Wafers are measured by diameter, commonly 200mm or 300mm; larger wafers yield more chips per manufacturing run.

See alsoDieFabYieldLithography

Die

An individual chip as it exists on the wafer, before it is separated and packaged. A wafer is patterned as a grid of identical dies, which are then cut apart and tested.

See alsoWaferPackagingYield

Fab

Short for fabrication plant: the factory in which semiconductor wafers are processed. Fabs are among the most capital-intensive industrial facilities in the world, requiring cleanroom environments, specialist equipment and highly stable utilities.

See alsoFabricationCleanroomFoundry

Fabrication

The sequence of processes that turns a blank wafer into finished circuits, including depositing thin films, patterning them using lithography, etching away unwanted material, and introducing impurities to alter electrical behaviour. A single advanced chip may require several hundred process steps.

See alsoLithographyFabYield

Cleanroom

A controlled environment in which airborne particles, temperature, humidity and vibration are tightly regulated. Semiconductor features are far smaller than a speck of dust, so a single particle landing on a wafer can destroy a chip.

See alsoFabYield

Lithography

The patterning step in chip manufacturing. Light is projected through a mask onto a light-sensitive coating on the wafer to define circuit features, which are then developed and etched. Lithography equipment is the most technically demanding and expensive category of semiconductor tooling.

See alsoFabricationNodeWafer

Yield

The proportion of chips on a wafer that work correctly. Because manufacturing costs are largely fixed per wafer, yield is one of the primary determinants of semiconductor profitability.

See alsoDieTestingFabrication

Node

The label given to a generation of semiconductor manufacturing process, historically expressed in nanometres, such as 5nm or 3nm. Modern node names are marketing designations for a generation of process technology rather than a literal measurement of any single feature.

See alsoLithographyTransistor

Packaging

Enclosing a finished die in a protective housing that connects it electrically and thermally to the wider system. Packaging determines much of a chip's real-world power consumption, heat behaviour and physical size.

See alsoAdvanced packagingDieChiplet

Advanced packaging

Techniques that combine multiple dies in a single package, or stack them vertically, to increase performance and bandwidth without shrinking the transistors themselves. Advanced packaging has become a central route to improving chip performance as further shrinking becomes harder and more expensive.

See alsoPackagingChipletDie

Chiplet

A smaller, functionally specialised die designed to be combined with other dies inside one package. Chiplet designs allow different functions to use the most appropriate manufacturing process, improving yield and flexibility compared with one very large monolithic chip.

See alsoAdvanced packagingDieYield

Testing

The measurement and verification of chips during and after manufacture, to confirm they meet electrical and performance specifications. Testing takes place both on the wafer and after packaging, and specialist test equipment and services form a distinct part of the supply chain.

See alsoYieldPackaging

Tape-out

The milestone at which a completed chip design is finalised and sent to a manufacturer to be made. Tape-out is a significant commercial and engineering event because subsequent changes require a new manufacturing run.

See alsoEDA (electronic design automation)FablessFoundry

Business models

Fabless

A semiconductor company that designs and sells chips but does not own manufacturing facilities, instead contracting production to a foundry. The fabless model lowers capital requirements and is the dominant model among UK chip companies.

See alsoFoundryIDM (integrated device manufacturer)Semiconductor IP

Foundry

A company that manufactures chips designed by other companies. Foundries sell manufacturing capacity and process technology rather than their own chip products, and the largest are among the most strategically significant companies in global technology.

See alsoFablessFabIDM (integrated device manufacturer)

IDM (integrated device manufacturer)

A semiconductor company that both designs and manufactures its own chips, and often packages and tests them too. The model requires very large capital investment but gives close control over process technology.

See alsoFablessFoundryFab

Semiconductor IP

Pre-designed, licensable building blocks of chip functionality — such as processor cores, interfaces or memory controllers — that other companies incorporate into their own chip designs. Licensing semiconductor intellectual property is a long-standing UK strength.

See alsoFablessEDA (electronic design automation)CPU (central processing unit)

EDA (electronic design automation)

The specialist software used to design, simulate and verify chips before they are manufactured. No modern integrated circuit can be produced without electronic design automation tools.

See alsoTape-outSemiconductor IPASIC (application-specific integrated circuit)

Materials

Compound semiconductor

A semiconductor made from two or more elements rather than from silicon alone. Compound semiconductors can handle higher voltages, higher frequencies, higher temperatures and light emission more effectively than silicon, which makes them important for power electronics, radio frequency components, photonics and electric vehicles.

See alsoSilicon carbide (SiC)Gallium nitride (GaN)Gallium arsenide (GaAs)Photonics

Silicon carbide (SiC)

A compound semiconductor used for high-voltage, high-efficiency power electronics. Silicon carbide devices reduce energy losses in applications such as electric vehicle drivetrains, charging infrastructure and renewable energy conversion.

See alsoCompound semiconductorGallium nitride (GaN)

Gallium nitride (GaN)

A compound semiconductor used in efficient power conversion, radio frequency amplification and light emission. Gallium nitride allows smaller, cooler and more efficient power electronics than silicon at comparable ratings.

See alsoCompound semiconductorSilicon carbide (SiC)Photonics

Gallium arsenide (GaAs)

A compound semiconductor with high electron mobility and useful optical properties, widely used in radio frequency components, satellite and defence electronics, photonic devices and solar cells.

See alsoCompound semiconductorPhotonics

Photonics

The generation, control and detection of light for practical use. In the semiconductor context, photonics covers lasers, optical sensors and photonic integrated circuits, which move data using light rather than electrical current — important for data centre interconnects, telecommunications, sensing and quantum technologies.

See alsoCompound semiconductorGallium nitride (GaN)Integrated circuit (IC)

Chips and compute

ASIC (application-specific integrated circuit)

A chip designed for one particular task rather than for general-purpose computing. Application-specific integrated circuits offer better performance and efficiency than general-purpose processors for that task, at the cost of flexibility and higher upfront design expense.

See alsoFPGA (field-programmable gate array)AcceleratorEDA (electronic design automation)

FPGA (field-programmable gate array)

A chip whose logic can be reconfigured after manufacture. Field-programmable gate arrays are used for prototyping, for low-volume products and where hardware behaviour must be updated in the field.

See alsoASIC (application-specific integrated circuit)Accelerator

CPU (central processing unit)

The general-purpose processor that runs most of a computer's instructions. Central processing units are designed for flexibility across a very wide range of tasks rather than maximum throughput on any single one.

See alsoGPU (graphics processing unit)NPU (neural processing unit)Semiconductor IP

GPU (graphics processing unit)

A processor built around large numbers of parallel arithmetic units. Originally created for rendering graphics, graphics processing units are now the mainstay of training large artificial intelligence models because that work is highly parallel.

See alsoCPU (central processing unit)AcceleratorInference

NPU (neural processing unit)

A processor designed specifically for the mathematics used by neural networks. Neural processing units are common in phones, laptops and embedded devices, where they run artificial intelligence workloads at low power.

See alsoAcceleratorInferenceGPU (graphics processing unit)

Accelerator

Any chip that takes a specific workload away from the general-purpose processor to run it faster or more efficiently. In artificial intelligence, accelerator usually refers to hardware optimised for training or running machine learning models.

See alsoGPU (graphics processing unit)NPU (neural processing unit)ASIC (application-specific integrated circuit)Inference

Inference

Running a trained artificial intelligence model to produce an output, as distinct from training the model in the first place. Inference is now the larger and faster-growing share of everyday AI compute demand, which is why specialised inference hardware has become a policy and investment priority.

See alsoAcceleratorNPU (neural processing unit)GPU (graphics processing unit)

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