Course:EOSC311/2025/Geological Sources for Semiconductor Materials

This project is about the geological origins and extraction of important materials used in the semiconductor industry, such as silicon, gallium, tantalum, tin, indium, and rare earth elements. It explores the importance of semiconductor materials in modern applications and the role geologists have in identifying and analyzing mineral deposits. The project discusses key ongoing issues for the semiconductor industry, such as physical resource scarcity, geographic supply concentration, environmental sustainability, and ethical implications of the materials' extraction process. Overall, this project emphasizes the need for responsible sourcing, and mentions potential strategies to reduce the risk of resource scarcity in the semiconductor industry.

Statement of connection

The computer science industry relies heavily on semiconductors, which are a necessary component for modern computers and other electronic devices. Semiconductors like silicon allow us to build transistors, and from there, the proper hardware for memory and processing units can be produced. These components conduct logical operations and store data, which is the backbone of computers. We are able to regulate the conductivity of semiconductors, which facilitates the circuits needed to provide electric flow to computers. It is safe to say that computer science would not exist without the support of semiconductors.

Why I Chose It

My goal before beginning my work on this project was to gain a deeper understanding of the materials that give life to our digital world. To develop this project, I wanted to investigate the idea that computers rely on semiconductor material components. This would require me to learn about how raw elements are transformed into the processors that power nearly every electronic device. I also wanted to learn more about the geological origins of these materials, and the ethical and environmental implications of their extraction.

I hope that students of all disciplines who stumble upon this can discover the importance of specific raw materials in shaping the modern technology we rely on every day. From computers to smartphones, semiconductors are the core of our digital world. Understanding where these materials come from and how they’re used not only deepens our technical knowledge but also encourages more responsible actions about global equity in the tech industry.

Overview of Semiconductor Materials

Semiconductor 3DMAX-A media processor developed by LG in 2016.

Semiconductor materials are substances with an electric conductivity in between conductors and insulators. They are able to conduct electric currents, which is essential for the functionality of electronics like computers. We can control the conductivity of semiconductors to an extent through doping, a process where tiny impurities are mixed into semiconductor material. This adds conductivity by adding donor atoms.

The most widely used semiconductor is silicon, mainly because of its stability, high abundance, and since its properties are understood very well. Silicon is the foundation of most integrated circuits and is especially coveted in the manufacturing process due to its robustness and relatively low extraction and purification costs.

The effectiveness of semiconductor materials is largely dependent on the purity of the material. Silicon requires a single crystal structure with an extraordinarily high purity of 99.999999999%. Semiconductors that have a single crystal structure are advantageous due to the stability of the structure.

Germanium was a popular semiconductor material in the past, but much of its use has been replaced by silicon due to its poor thermal stability. Although it is less prevalent today, germanium is still used in LEDs and is needed to make gallium arsenide, which is the second most popular semiconductor.

Gallium arsenide is a compound of gallium and arsenic. The advantage of gallium arsenide is its quick electronic response, which makes it very suitable for high frequency applications like wireless connectivity.

Geological Formation and Sources of Silicon

Silicon Origins and Formation

Open pit mining is a mining technique that involves extracting materials from a pit in the ground.

Silicon is the second most abundant element in the earth’s crust, accounting for over 25% of the crust by weight. This silicon naturally occurs mostly as silicon dioxide (SiO2) or silicates. The extracted form of silicon is not found naturally, and instead must be extracted from silicate materials. The most common silicate materials are sand and quartz, which silicon is mainly extracted from. Much of this sand is abundant, easily minable, and relatively straightforward to process. In most cases, silica mining uses open pits with standard mining equipment.

Quartz can form through the process of cooling magma. Magma contains many minerals, including silicon and oxygen. Over long periods of time, silicon and oxygen can crystallize and create the tetrahedral structures necessary for quartz crystal formation.

Quartz can be pure if it is formed from a silica-rich composition. Not all quartz is suitable for industrial use in electronics. High purity quartz is needed for semiconductor grade silicon, but only small quantities of silicon are processed that meet the semiconductor purity requirement 8. The quality of quartz can depend on its purity and where it was quarried.

Global Silicon Production

Significant global regions for mining high quality silica include China, the United States, Brazil, and Russia. The vast majority of global silicon production is in China, which processes approximately 80% of the world’s silicon. However, other major silicon-producing countries such as Russia, Brazil, and the United States also have significant silicon reserves.

Other Important Semiconductor Elements and Their Sources

While silicon largely dominates the semiconductor industry, a variety of other key elements are critical in the functionality of computers and other electronic devices. Elements such as gallium, tantalum, tin, and indium see widespread use in high quality semiconductors. Rare earth elements (REEs) also play an important role in modern technology. The geological challenges of sourcing these elements stem from their low concentration deposits, making extraction logistically difficult. Since many of these materials are byproducts, their availability is dependent on the supply of other materials, which can bottleneck supply.

Gallium

Raw crystals of 99.999% gallium.

Gallium is often used alongside arsenic in gallium arsenide (GaA) and alongside nitrogen in gallium nitride (GaN). GaA and GaN semiconductors are in high demand due to their practical applications in high frequency network infrastructures. Gallium is not mined directly, but is produced as a byproduct of bauxite (aluminum ore) and in some cases, zinc processing. A vast majority of the world’s gallium production comes from China, accounting for approximately 98% of global production.

Tantalum

Tantalum (Ta) is a semiconductor element that is heavily used in high performance capacitors, which are used in low voltage electronics due to their ability to store electricity for short periods of time. The reliability of tantalum over wide ranges of temperature makes it the best element material for capacitors. Most of the world’s tantalum production comes from the Democratic Republic of Congo, accounting for approximately 40% of global production.

Tin

Soldering a circuit using a primarily tin alloy.

Tin has a critical function in modern electronics as a composite metal in solder used to connect other components on an electronic circuit. Half of global tin consumption stems from its usage in solder. The current supply chain of tin is scarce, with demand greatly outpacing supply, and this pattern is expected to continue in the future. China, Indonesia, and Burma are the world’s leading producers of tin, with China accounting for approximately 25% of global tin production, and Indonesia and Burma accounting for approximately 20% each.

Indium

Indium is used as a semiconductor material used in electronic displays. There is also great potential for indium to be used for solar cells along with copper, gallium, and selenide (CIGS), but silicon is still the primary element for this purpose. China is currently the leading producer of indium in the world, accounting for approximately 70% of global production. South Korea, Canada, and Japan are also major producers of indium.

The Role of Geologists in the Semiconductor Supply Chain

Mineral Reserve Identification and Analysis

Geologists conducting on-site analysis in Voisey's Bay Mine, Labrador, Canada.

Geologists conduct various techniques to identify potential mineral reserves. They use a combination of geologic mapping, remote sensing, and on-site fieldwork to find favourable geological structures, rock compositions, faults, and veins. These characteristics indicate the potential to host minerals like lithium, gallium, tantalum, tin, indium, and rare earth elements. Using modern sensing technologies such as hybrid pixel detectors and diodes, geologists can determine the presence or absence of mineral elements before the drilling process begins.

Once a mineral reserve is identified, geologists perform drill core analysis to create high resolution images. They are able to characterize geological zones based on the material composition of the rock formations. Modern geologists are able to reconstruct a deposit’s geological history through field and laboratory analysis. Mine geologists can then model the ore body and predict ore variations and increase cost efficiency.

Environmental Assessments

Geologists also conduct environmental risk assessments to determine the risks of undertaking mineral extraction and processing. They contribute to environmental sustainability by managing natural resources and developing new methods that minimize ecological degradation. Environmental geologists are also involved in managing waste and preventing water contamination to control the environmental downsides of mining.

Ethical and Environmental Considerations

In addition to the environmental degradation that occurs during mineral extraction, the processing of semiconductor materials is a highly water intensive activity that consumes toxic chemicals. However, geologists and engineers are constantly innovating and seeking ways to transition to sustainable practices.

Degraded landscape after long-term strip mining.

Many key electronic material components, such as tantalum, tin, and tungsten are sourced and mined in regions where profits from mineral extraction facilitate human rights violations and armed conflicts. In the Democratic Republic of Congo, where 40% of the world’s tantalum supply is sourced, trade proceeds from tantalum is often used to fuel civil wars in the region. Cases of child exploitation are also fueled by mining in underdeveloped areas.

Geologists are responsible for ensuring that minerals are sourced ethically. In addition to identifying economically viable mineral reserves, geologists must work with local communities of mining sites to prevent increases in crime and exploitation in these areas.

Companies have recently been implementing more methods to source minerals ethically and sustainably. The Conflict Minerals Reporting Template (CMRT) is an industry-backed template for collecting data on mineral sourcing throughout the supply chain. The Responsible Minerals Initiative (RMI) is a certification initiative that encourages mineral refiners to adhere to ethical and environmental standards.

Resource Scarcity and Future Challenges

The semiconductor industry is facing issues of physical resource scarcity for key materials such as gallium, indium, and tin. These materials are often the rarest, are at most risk of depletion, and have high demand relative to supply due to their modern technological applications.

However, most of the semiconductor industry’s raw material risk can be attributed to supply concentration, where global supply is heavily reliant on one or a few countries. Silicon is an abundant material, but approximately 80% of silicon is sourced from China. Africa and China account for approximately 70% of global tantalum supply. China alone also accounts for 98% of global gallium production and 70% of global indium production, despite their share of global reserves for these minerals not nearly reflecting their share of global mineral production. The geographical concentration of these mineral supplies could threaten the semiconductor industry, which highlights the need for diversified supply chains when feasible.

To help mitigate the risk of raw material scarcity, initiatives to recycle materials throughout the manufacturing process can reduce the need for raw materials. Other strategies to address scarcity and supply chain risk include developing new technology with lower raw mineral requirements, and finding ways to replace high risk materials with similarly performing materials.

Conclusion

As the demand for semiconductors continues to rise worldwide, the need for sustainable, ethical, and diversified sourcing of raw materials is increasingly important. This project has highlighted the importance of geological science when extracting, analyzing, and managing the impacts of raw materials. Geologists, along with engineers, computer scientists, and policy makers, will be critical in addressing the challenges of the semiconductor industry and moving us in the right direction as we continue to discover new geological sources and technological uses for raw materials. Ultimately, understanding the geological, environmental, and ethical aspects of semiconductor production enables us to design smarter technology, supply chain systems, and production processes moving forward.

References

This Earth Science resource was created by Course:EOSC311.