What is the difference between metal silicon with oxygen and no oxygen

Metallic silicon is a silicon material with a purity of up to 99.999%. As the core basic material of modern industry, it is widely used in cutting-edge fields such as solar photovoltaics, semiconductors, and integrated circuits.

In industrial production, depending on whether oxygen is introduced during the smelting process, metallic silicon can be divided into oxygen-permeable metallic silicon and non-oxygen-permeable metallic silicon. These two process paths not only determine the microstructure of the silicon material, but also directly affect its physical and chemical properties and application scenarios.



 

Introduction to metal silicon with oxygen

Oxygenated silicon metal refers to silicon materials produced by introducing oxygen during the smelting process. Through redox reactions in a heating furnace (e.g., Si + O₂ → SiO₂), oxygen reacts with raw silicon to form a stable silicon dioxide (SiO₂) layer on the surface.

This process enhances impurity removal (e.g., iron, aluminum) and results in silicon with a purity typically ranging from 99.5% to 99.9%. The surface SiO₂ layer acts as an insulator and corrosion-resistant barrier, distinguishing it chemically and physically from non-oxygenated counterparts.

Introduction to non-oxygenated silicon metal

Non-oxygenated silicon metal is produced without intentional oxygen introduction during processing. It retains a pure silicon structure (Si) without a surface oxide layer, leading to higher chemical reactivity. This method is often used for high-purity applications, where silicon can be further refined to 99.9%–99.9999% purity (e.g., 9N-grade silicon for semiconductors).

The absence of oxygen allows for precise control of electrical conductivity, making it critical for electronics and advanced materials.

What is the difference between metal silicon with oxygen and non-oxygenated silicon metal?

Structurally, the silicon dioxide layer on the surface of through-oxygenated silicone has a stable chemical structure that provides good insulating properties and chemical stability. On the other hand, the structure of non-oxygenated silicon is relatively more homogeneous and has higher chemical activity.

In terms of physical properties, the hardness and abrasion resistance of oxygenated silicone is usually better than that of non-oxygenated silicone due to the silicon dioxide layer on the surface. The electrical conductivity of non-oxygenated silicon is relatively good.

In terms of electrical properties, the insulating properties of silicon oxychloride make it widely used in the manufacture of integrated circuits to effectively prevent current leakage and short-circuit phenomena. Non-peroxygenated silicon is commonly used in the manufacture of conductive parts in semiconductor devices due to its good electrical conductivity. 

This distinction has important implications for material applications. In the manufacture of integrated circuits, the good insulating properties and stability of through-oxygenated silicon are key to ensuring chip performance and reliability. In contrast, the high conductivity of unoxidized silicon makes it important in scenarios where efficient conductivity is required, such as in certain specific transistor structures.

In addition, the chemical stability of non-perovskite silicon enables it to maintain its performance in harsh environments, while non-perovskite silicon is more advantageous in applications that require very high conductivity and relatively good environmental conditions.

In the production of silicon metal, the two processes of oxygenation and de-oxygenation each have their own unique advantages and are suitable for different production needs and application scenarios.

Advantages of metal silicon with oxygen

Highly efficient impurity removal: The oxygenation process can quickly and effectively remove impurities such as iron and aluminum from silicon metal through redox reactions. Compared with the non-oxygenated process, the impurity removal efficiency can be increased by 40%-60%, enabling the silicon purity to reach more than 99.5%, laying the foundation for the production of high-quality silicon materials.

Enhanced production efficiency: Oxygen is introduced into the smelting process, which promotes uniform heating of the silicon melt and greatly improves the uniformity of the furnace temperature. This not only helps to shorten the smelting cycle by 20%-30%, but also improves the utilization rate of the production equipment, which is very suitable for large-scale industrialized production.

Optimizing material properties: The oxygenation process has a positive effect on the crystal structure of the silicon body, improving the integrity of the crystal structure and thus enhancing the physical and chemical properties of the silicon.

Advantages of non-oxygenated silicon metal

Simple and easy to control: The oxygen-free process uses quartz sand and charcoal as raw materials for high-temperature reduction, eliminating the need for complex oxygen feed and redox processes and simplifying the production process by more than 50%. This makes the process less difficult to operate and easier to control, especially suitable for small-scale production.

Energy saving and consumption reduction: Since the oxygen-free process does not consume a large amount of oxygen, it has an obvious advantage in terms of energy costs. Additional equipment and safety costs associated with the use of oxygen can also be avoided.

Outstanding high purity potential: the non-oxygenation process has a natural advantage in the preparation of high-purity silicon metal. Through multi-stage distillation, zone melting and other subsequent purification means, the purity of silicon can be increased to 99.9%-99.9999%, which meets the stringent requirements of semiconductors, photovoltaics and other high-end fields on the purity of the material.

What is metal silicon with oxygen used in industry?

Metallurgical industry (deoxidation and alloying)

Steelmaking, casting: as a deoxidizer (such as ferrosilicon, calcium silica-aluminum composite deoxidizer), through the reaction between silicon and oxygen to generate silicon dioxide (SiO₂) to reduce the oxygen content in steel, and at the same time, as an alloying element to regulate the performance of steel (such as to improve strength, hardness).

Cast iron production: used in pregnancy treatment, promote graphitization, improve the mechanical properties of cast iron (such as toughness, wear resistance).

Aluminum alloy additives: Silicon Aluminum alloy containing silicon oxide is added in aluminum smelting to regulate the fluidity and strength of aluminum liquid.

Chemical industry (silicon compound preparation)

Production of sodium silicate (water glass): quartz sand containing silicon oxide is used as raw material and reacted with caustic soda to produce sodium silicate, which is used in the manufacture of adhesives, detergents, and refractories.

Preparation of silicone intermediates: Refining industrial silicon through ores containing silicon oxide (such as quartz), and then further synthesizing silicone products such as silicone oil, silicone rubber, etc. (but the purity requirement is lower than that of semiconductor-grade silicon).

Refractories and Ceramics

Refractory bricks and kiln materials: Utilizing the high melting point characteristics of silicon dioxide (SiO₂), we manufacture high-temperature-resistant refractory materials for use in metallurgical furnaces, glass kilns, and other high-temperature equipment.

Ceramic raw materials: used as a component of blanks or glazes to improve the hardness and chemical stability of ceramics.

What is non-oxygenated silicon metal used for?

Oxide-free silicon metal (very low oxygen content, purity is usually ≥ 99.9%) is mainly used in electronic information, new energy, high-end manufacturing and other fields that require very high purity.

High-end alloys and special materials

Aerospace alloys: Used in the preparation of high-purity silicon aluminum alloys (such as aero-engine components), to enhance the lightweight and corrosion resistance of the material.

Special Ceramics and Coatings: used as raw material for precision ceramics (e.g. silicon nitride ceramics) or for high-temperature coating materials (e.g. silicide coatings to improve metal oxidation resistance).

Semiconductor and Electronics Industry

Chip Manufacturing: Semiconductor-grade high-purity silicon (purity of 99.999999999% or more, referred to as “9N silicon”) is made into silicon wafers by the process of crystal pulling, slicing, photolithography, etc., which is the core substrate for integrated circuits (CPU, memory, etc.).

Photovoltaic (solar) industry

Solar panels: Highly pure polysilicon (purity of 99.999% or more) is made into ingots/rods through casting or crystal pulling processes, and cut into photovoltaic cells to convert light energy into electricity.

Conclusion

In conclusion, the difference between oxygenated and unoxygenated silicon, each with its own unique properties, determines their suitability in different fields and application scenarios, providing a variety of choices for the development of the modern electronics and semiconductor industries.