Silicon (Si) is a light chemical element that combines with oxygen and other elements to form silicates. Silicon in the form of silicates constitutes more than 25% of the Earth’s crust. Silica (SiO2) as quartz or quartzite is used to produce silicon ferroalloys and silicon metal.   Demand for silicon ferroalloys is driven principally by the production of cast iron and steel.   Silicon metal, which generally is produced like ferrosilicon in submerged-arc electric furnaces, is used not as a ferroalloy, but rather for alloying with aluminum and for production of chemicals, especially silicones. Small quantities of silicon are processed into high-purity silicon for use in the semiconductor industry.

Why Is Silicon A Critical Raw Material?

Silicon stands out as a critical raw material due to its essential role in multiple strategic industries and the concentration of global production in a few countries, particularly China. China accounted almost 80% of total global estimated production of silicon materials in 2024, creating significant supply chain vulnerabilities for nations dependent on imports. The importance of silicon has been formally recognized internationally, with Canada’s Minister of Energy and Natural Resources added silicon metal to its critical minerals list and silicon metal was included as a strategic raw material in the European Union’s Critical Raw Materials Act in 2024. This designation reflects silicon’s fundamental importance in semiconductor chips, electronics markets, and solar power generation.

The strategic significance of silicon is underscored by recent U.S. policy initiatives and market dynamics. Following the CHIPS and Science Act of 2022, the U.S. Department of Commerce announced as of October 2024 preliminary agreements with 20 companies for 32 semiconductor manufacturing projects in 20 States, with nearly $34 billion in direct funding allocated. The domestic production situation reveals concerning dependencies: Most ferrosilicon was consumed in the ferrous foundry and steel industries, predominantly in the Eastern United States, while Ferrosilicon and silicon metal were produced at five facilities in 2024, all east of the Mississippi River. The U.S. maintains varying degrees of import reliance, with ferrosilicon showing greater than 50% import dependency in most recent years.

The critical nature of silicon extends beyond its current applications to future technologies, particularly in renewable energy. The restart of solar-grade polysilicon production facilities demonstrates the material’s importance in clean energy transitions. As part of a new integrated silicon-based solar supply chain facility in Georgia, production of silicon solar modules began in April 2024, marking the first U.S. production of solar-grade wafers since 2016. However, the industry faces significant challenges, as evidenced by REC Silicon’s December 2024 decision to cease polysilicon production at its Moses Lake facility due to quality standard issues, highlighting the technical difficulties in establishing domestic supply chains for high-purity silicon products.

Market volatility further emphasizes silicon’s critical status. Price fluctuations have been substantial, with Silicon metal prices ranging from 96.84 cents per pound in 2020 to 361.86 cents per pound in 2022, before moderating to around 180 cents in 2023-2024. The concentration of production capacity creates supply risks – Silicon materials were produced at six facilities in 2023, all east of the Mississippi River, with one facility idling by the end of 2023 due to poor market conditions. This geographic concentration, combined with high import reliance and the material’s indispensable role in semiconductors, solar panels, and aluminum alloys, firmly establishes silicon as a critical raw material requiring strategic policy attention to ensure supply security.

20 Interesting Facts About Silicon

1. Second most abundant element – Silicon makes up 27.7% of Earth’s crust by mass, second only to oxygen, and is found in nearly all rocks, sand, and clays.
2. Semiconductor superstar – Silicon has four valence electrons, making it a perfect semiconductor that can be “doped” with other elements to precisely control its electrical conductivity.
3. Crystal structure – Pure silicon forms a diamond cubic crystal structure, the same as diamond, giving it remarkable mechanical properties and making it extremely hard.
4. Band gap goldilocks – Silicon’s band gap of 1.12 eV at room temperature is ideal for electronic applications – not too high (insulator) and not too low (conductor).
5. Solar cell efficiency – Silicon can convert up to 26.7% of sunlight into electricity in laboratory conditions, approaching the theoretical maximum of 29.4% for single-junction silicon solar cells.
6. Melting point – Silicon melts at 1,414°C (2,577°F), but interestingly, it expands by about 9% when it solidifies, similar to water turning to ice.
7. Isotope stability – Silicon has three stable isotopes: Si-28 (92.2%), Si-29 (4.7%), and Si-30 (3.1%), with Si-28 being used in quantum computing research.
8. Oxide formation – Silicon spontaneously forms a protective silicon dioxide (SiO₂) layer just 1-2 nanometers thick when exposed to air, crucial for semiconductor manufacturing.
9. Thermal conductivity – Pure silicon has a thermal conductivity of 149 W/(m·K), about one-third that of copper, making it useful for heat management in electronics.
10. Photoluminescence – While bulk silicon is a poor light emitter, silicon nanocrystals smaller than 5 nanometers can emit visible light due to quantum confinement effects.
11. Neutron transmutation – Silicon can be uniformly doped by exposing it to neutron radiation, converting Si-30 to phosphorus-31, creating n-type semiconductors with exceptional uniformity.
12. Zone refining purity – Silicon can be purified to 99.9999999% (9N) purity through zone refining, making it one of the purest materials produced industrially.
13. Silicene – Scientists have created silicene, a two-dimensional allotrope of silicon analogous to graphene, which exhibits unique electronic properties including a tunable band gap.
14. Biocompatibility – Silicon is biocompatible and biodegradable in the human body, breaking down into silicic acid, making it useful for temporary medical implants.
15. Optical properties – Silicon is transparent to infrared light with wavelengths longer than 1.1 micrometers, making it useful for infrared optics and thermal imaging.
16. Strain engineering – Applying mechanical strain to silicon can increase electron mobility by up to 80%, a technique used in modern processors to boost performance.
17. Quantum dots – Silicon quantum dots can be tuned to emit different colors of light by changing their size, with applications in displays and biomedical imaging.
18. Superconductivity – While normal silicon is not superconductive, heavily boron-doped silicon becomes superconductive below 0.35 K under high pressure.
19. Chemical versatility – Silicon forms more compounds than any other element except carbon, with over 30,000 known silicon-containing compounds.
20. Moore’s Law enabler – Silicon transistors have been scaled down to just 3 nanometers in commercial production, with each chip containing billions of transistors switching billions of times per second.

Thanks for reading!