As a purified high-purity silicon material, silicon material is the "food" of modern industry. Its uses are mainly concentrated in the following three areas:
1. Photovoltaic industry: the cornerstone of clean energy
The photovoltaic industry consumes more than 80% of the world's silicon materials (according to the 2023 annual report of the China Photovoltaic Association). Through the CZ method or ingot casting method, silicon materials are processed into:
1. Monocrystalline silicon rods: using 99.9999% (6N) pure silicon materials, cut into silicon wafers to make high-efficiency solar cells such as PERC and TOPCon, with a conversion efficiency of more than 24%
2. Polycrystalline silicon ingots: using 99.99% (4N) pure silicon materials, with lower cost but slightly lower efficiency (about 18-20%), commonly used in distributed photovoltaic power stations
2. Semiconductor industry: the starting point of chip manufacturing
Semiconductor-grade silicon materials (purity 99.999999%-99.999999999%, 9N-11N) account for about 15% of global silicon material consumption (SEMI 2024 data). Key applications include:
1. Wafer manufacturing: Silicon materials are pulled, cut and polished to form 8/12-inch wafers for the production of integrated circuits such as CPUs and memories
2. Power devices: Power electronic devices such as automotive-grade IGBT chips require the use of heavily doped silicon materials of more than 8 inches
3. Special needs: Aerospace-grade chips have strict requirements on the radioactive residue of silicon materials (need to be <0.01Bq/kg)
III. Other industrial applications: diversified uses
The remaining approximately 5% of silicon materials are used for:
1. Special glass: High borosilicate glass tubes are used for medical packaging and can withstand high-temperature sterilization at 150°C
2. Silicon-based materials: The tensile strength of silicone rubber can reach 10-12MPa (GB/T 5280 standard), which is widely used in the manufacture of seals
3. Chemical catalysts: The conversion rate of silicon-loaded catalysts in polyethylene production exceeds 85%
Two key indicators of silicon materials:
1. Purity classification: Solar grade (6N) silicon material impurity content <0.0001%, electronic grade (9N and above) impurity content <1 billionth
2. Global usage: In 2023, photovoltaic grade silicon material consumption will be about 960,000 tons, and semiconductor grade will be 180,000 tons (Bloomberg New Energy Finance statistics)
With the popularization of N-type battery technology and the explosion of AI chip demand, it is expected that by 2025, the purity of photovoltaic grade silicon materials will generally increase to 7N, and the market size of semiconductor grade silicon materials will grow to 260,000 tons/year.