Semiconductors are materials forming the basis of computer chips. They're used in consumer electronics like smartphones; solar panels, robots, EVs, spacecraft and industrial machinery.
The five major semiconductor materials are silicon, graphene, germanium, gallium arsenide, and gallium nitride.
Semiconductors conduct electricity under some conditions, or act as insulators. They're essential crucial for building transistors and other electronic components.
Silicon remains the dominant force due to its abundance and well-established manufacturing infrastructure. Materials like graphene, germanium, gallium arsenide, and gallium nitride are geared to expanding market niches and leading innovation where silicon falls short.
1. Silicon (Si)
Silicon, a metalloid, is the most recognized semiconductor material. It's often considered the heart of the electronics industry.
With a band gap of 1.1 eV, silicon efficiently conducts electricity. Found abundantly in nature, it's prevalent in sources like quartz, sand, and clay.
Key production countries include the United States, China, and Brazil. Silicon is extracted from silicon dioxide (SiO2) in sand or quartzite.
Silicon used in computer chips, photovoltaic cells, consumer electronics.
The extraction of silicon, while energy-intensive, results in high-purity silicon needed for electronic components.
Properties: Silicon is abundant, relatively inexpensive, and its properties are well-understood. It forms strong, stable oxides to create the insulating layers in integrated circuits. It exhibits a moderate electron mobility.
Current Uses: Microprocessors, memory chips (DRAM, Flash), diodes, transistors, solar cells. It's the dominant material in the vast majority of electronic devices.
Suitability as a Semiconductor: Excellent due to its abundance, affordability, stability, and well-developed manufacturing processes based on its properties.
Natural Occurrence: The second most abundant element in the Earth's crust. Found primarily in silica (silicon dioxide, SiO2) like quartz and sand, and in silicates, which make up many rocks.
Graphene has unique properties that not be found in other non-metallic materials. It's considered a semi-metal as it shares some properties with semi-conducting metals.
Key Producer Countries: China, Australia, Russia, United States, Brazil.
Extraction Techniques: A common approach to refining silicon is the carbothermic reduction process, in which silica is heated to high temperatures with coke, yielding silicon and carbon monoxide.
The silicon is then purified using techniques like the Czochralski process or the Float Zone process to achieve the ultra-high purity required for semiconductor applications.
In the Czochralski method crystal growth is used to obtain single crystals of semiconductors, metals, salts and synthetic gemstones. It's used in 90% of semiconductor manufacturing.
The float zone process or zone melting, is a crucible-free crystal growth technique. A molten zone is held between two solid rods by surface tension, enabling growth of high-purity single crystals.
Market Stats: The global silicon market, valued at around $18.27 billion in 2024, is projected to exceed $35.58 billion by 2034, growing at a CAGR of 6.89% from 2025 to 2034. It's driven by rising demand in industries like automotive, construction, electronics, and healthcare.
2. Graphene (C)
Though naturally occurring graphene is rare, it can be synthesized from graphite. Methods for extraction include chemical vapor deposition (CVD) and liquid-phase exfoliation, factors in its increasing use in technology.
Properties: Graphene is a single-layer sheet of carbon atoms arranged in a hexagonal lattice. It has exceptional electron mobility, incredible strength, and high thermal conductivity.
Current Uses: Still in its early stages of widespread adoption, graphene has applications in sensors, composites, batteries, and transparent conductive films, with significant potential in flexible electronics is significant.
Suitability as a Semiconductor: While pure graphene has no band gap, methods are explored to induce a band gap through chemical modification or structural manipulation.
A band gap or energy gap refers to the energy difference between the valence band, where electrons are attached to atoms, and the conduction band, where electrons can move freely.
Natural Occurrence: Found in graphite, the common form of carbon used in pencils.
Key Producer Countries: China, Brazil, India, Canada, and Russia.
Market Value: The global graphene market is valued at USD 1 billion in 2024. It's projected to reach $2.94 billion by 2029, growing at a CAGR of 24.0%
Extraction Techniques: Graphene production uses methods like mechanical exfoliation (peeling layers from graphite), chemical vapor deposition (CVD), and liquid-phase exfoliation. Each method offers trade-offs in terms of production scale, cost, and quality.
Interesting Facts: The Nobel Prize in Physics is awarded in 2010 to Andre Geim and Konstantin Novoselov for their groundbreaking experiments with graphene.
3. Germanium (Ge)
Today, germanium finds extensive use in fiber-optic systems and infrared optics, suited to high-performance devices like transistors. Growth is fueled by increasing demand in telecommunications and optics.
Properties: A metalloid, germanium is the first semiconductor material used extensively in transistors. It has higher electron and hole mobility than silicon but is more sensitive to temperature changes. It has a band gap of 0.66 eV, high electron mobility suitable for high-frequency and high-speed uses.
Current Uses: Detectors, infrared optics, high-frequency electronics, and as a substrate for advanced silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) used in wireless communication.
Suitability as a Semiconductor: Less suitable than silicon for mainstream applications due to its higher cost and temperature sensitivity, but valuable in niche areas for high mobility.
Natural Occurrence: Found sparsely in the Earth's crust, it's often associated with zinc and copper ores. Germanite is an ore of germanium.
Key Producer Countries: China, United States, Russia and Belgium.
Market Value: In 2024, the germanium market is estimated at $3.48 billion, with projections for growth to $5.02 billion by 2034, driven by a CAGR of 3.72%.
Extraction Techniques: Germanium is usually extracted as a byproduct of zinc or copper smelting. It's then purified using processes like zone refining or chemical purification.
Germanium's discovery is predicted by Dmitri Mendeleev, creator of the periodic table. He anticipates its properties before it's actually found.
4. Gallium Arsenide (GaAs)
Gallium arsenide (GaAs) is has superior electronic and optoelectronic properties. With a direct band gap of 1.43 eV, GaAs is adept at light emission, useful for LED technology and solar cells.
Properties: Gallium arsenide is a compound semiconductor formed by the elements gallium, a metal, and arsenic, a metalloid, with significantly higher electron mobility than silicon. It also shows a direct band gap, efficient for light emission.
Current Uses: Radio frequency (RF) amplifiers, high-speed digital circuits, light-emitting diodes (LEDs), laser diodes, and solar cells.
Suitability as a Semiconductor: Excellent for high-frequency applications where speed is paramount, but more expensive and difficult to process than silicon.
Natural Occurrence: It's not found in its pure form in nature. The constituent elements, gallium and arsenic, occur in trace amounts in various minerals.
Key Producer Countries (of Gallium): China, Germany, Kazakhstan, South Korea, Ukraine.
Key Producer Countries (of Arsenic): China, Morocco, Russia, Mexico.
Market Value: In 2024, the gallium market increases in price, reaching a 13-year high following export restrictions by China. Market size is estimated at $26.9 million with projections for further growth. The market is driven by demand from wireless communication and optoelectronics industries.
Extraction Techniques: Gallium is often extracted as a byproduct of aluminum production, from bauxite. Arsenic is obtained from smelting sulfide ores of copper, lead, and gold.
Gallium arsenide is then synthesized through processes like the Bridgman-Stockbarger method or Metal-Organic Chemical Vapor Deposition (MOCVD).
Gallium arsenide leads to the development of early LEDs.
5. Gallium Nitride (GaN)
Gallium nitride (GaN) emerges as an influential factor in the semiconductor field. Characterized by a wide band gap of 3.4 eV, GaN can handle high voltages and high-temperature environments
This makes it ideal for power electronics. Gallium nitride is a compound of metal gallium and non-metal gas nitrogen.
Properties: A wide-bandgap semiconductor gallium nitride needs more energy to excite electrons into conduction. This translates to higher breakdown voltage, higher operating temperature, and more power efficiency compared to silicon.
Current Uses: Power amplifiers in radio base stations, power switching devices in electric vehicles and power supplies, and LEDs in lighting and displays.
Suitability as a Semiconductor: Ideal for high-power and high-frequency applications for efficiency and integrity. It's rapidly replacing silicon in many power electronics applications.
Natural Occurrence: Like GaAs, GaN is not found in its pure form. The constituent elements, gallium and nitrogen, are obtained from other sources.
Key Producer Countries (of Gallium): China, Germany, Kazakhstan, South Korea, Ukraine.
Nitrogen is extracted from the atmosphere globally through various industrial processes.
Market Value: The gallium nitride market is experiencing rapid growth driven by demand in power electronics and RF applications.
The global GaN semiconductor devices market reaches USD 3.03 billion in 2023. It's driven by increasing demand for high-efficiency power devices and growing applications of GaN (gallium nitride) semiconductor devices.
The market is projected to grow at a CAGR of 26.3% between 2024 and 2032, reaching a value of USD 24.68 billion by 2032.
Extraction Techniques: Gallium is obtained as a byproduct of aluminum production. Nitrogen is extracted from the atmosphere through fractional distillation of liquid air.
Liquid air is air chilled to very low (cryogenic) temperatures, resulting in its condensation into a pale blue, fluid liquid. It's as a refrigerant and a source of oxygen, nitrogen, and other inert gases.
Gallium nitride is then grown epitaxially (layer by layer) on substrates like silicon carbide (SiC) or silicon (Si) using techniques like Metal-Organic Chemical Vapor Deposition (MOCVD).
MOCVD is used to deposit thin films of materials by using a vapor phase reaction of organometallic precursors. An organometallic compound is a compound that with a bond between a carbon atom and a metal atom.
GaN is the material used in many blue LEDs, which, combined with yellow phosphors, produce white light LEDs.
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