Based on purity and application areas, silicon materials can be divided into the following three categories:
1. Metallurgical grade silicon (MG-Si)
- Purity: 98%-99%
- Preparation process: electric arc furnace reduction of quartz sand
- Application: aluminum alloy, silicone monomer
- Industry data: Global production in 2023 is about 3.3 million tons (CRU Group statistics), unit price is about 15,000-20,000 yuan/ton
2. Solar grade silicon (SoG-Si)
- Purity: 99.9999%-99.999999% (6N-8N)
- Preparation process: modified Siemens method, fluidized bed method
- Application: photovoltaic cells
- Key indicators: carbon content <0.5ppm, oxygen content <10ppm (GB/T 25074-2020 standard)
3. Electronic grade silicon (EG-Si)
- Purity: ≥99.9999999% (9N-11N)
- Preparation process: trichlorosilane hydrogen reduction method
- Application: 12-inch wafers, CPU chips
- Industry barriers: 90% of global production capacity is concentrated in companies such as Wacker in Germany and Hemlock in the United States (SEMI 2022 data)