Electronic Grade Silicon Carbide Powder

As the core material of the third-generation semiconductors, silicon carbide (SiC) is playing an increasingly important role in high-tech fields such as new energy vehicles, photovoltaic energy storage, and 5G communications due to its excellent physical properties. At present, the synthesis of electronic-grade silicon carbide powder mainly relies on the improved self-propagating high-temperature synthesis method (combustion synthesis method). This method achieves efficient synthesis of silicon carbide through the combustion reaction of Si powder and C powder combined with an external heat source (such as induction coil heating).

Key Process Parameters Affecting the Quality of SiC Powder

1. Influence of the C/Si Ratio:

  The efficiency of SiC powder synthesis is closely linked to the silicon-to-carbon (Si/C) ratio. Generally, a C/Si ratio of 1:1 helps prevent incomplete combustion, ensuring a higher conversion rate. While a slight deviation from this ratio can initially increase the conversion rate of the combustion reaction, exceeding a C/Si ratio of 1.1:1 can lead to problems. Excess carbon may become trapped within the SiC particles, making it difficult to remove and affecting the purity of the material.

2. Influence of Reaction Temperature:

  The reaction temperature significantly influences the phase composition and purity of the SiC powder:

  - At temperatures ≤ 1800°C, primarily 3C-SiC (β-SiC) is produced.

  - Around 1800°C, β-SiC starts to gradually transform into α-SiC.

  - At temperatures ≥ 2000°C, the material is almost completely converted to α-SiC, which enhances its stability.

3.Effect of reaction pressure

The reaction pressure affects the particle size distribution and morphology of SiC powder. Higher reaction pressure helps to control the particle size and improve the dispersion and uniformity of the powder.

4.Effect of reaction time

The reaction time affects the phase structure and grain size of SiC powder: under high temperature conditions (such as 2000℃), the phase structure of SiC will gradually change from 3C-SiC to 6H-SiC; when the reaction time is further extended, 15R-SiC may even be generated; in addition, long-term high-temperature treatment will intensify the sublimation and regrowth of particles, causing small particles to gradually aggregate to form large particles.

Preparation Methods for SiC Powder

The preparation of silicon carbide (SiC) powder can be categorized into three main methods: solid phase, liquid phase, and gas phase, in addition to the combustion synthesis method.

1. Solid Phase Method: Carbon Thermal Reduction

  - Raw Materials: Silicon dioxide (SiO₂) as the silicon source and carbon black as the carbon source.

  - Process: The two materials are mixed in precise proportions and heated to high temperatures, where they react to produce SiC powder.

  - Advantages: This method is well-established and suitable for large-scale production.

  - Disadvantages: Controlling the purity of the resulting powder can be challenging.

2. Liquid Phase Method: Gel-Sol Method

  - Principle: This method involves dissolving alcohol salts or inorganic salts to create a uniform solution. Through hydrolysis and polymerization reactions, a sol is formed, which is then dried and heat-treated to obtain SiC powder.

  - Advantages: This process yields ultrafine SiC powder with a uniform particle size.

  - Disadvantages: It is more complex and incurs higher production costs.

3. Gas Phase Method: Chemical Vapor Deposition (CVD)

  - Raw Materials: Gaseous precursors such as silane (SiH₄) and carbon tetrachloride (CCl₄).

  - Process: The precursor gases diffuse and undergo chemical reactions in a closed chamber, resulting in the deposition and formation of SiC.

  - Advantages: SiC powder produced through this method is of high purity and is suitable for high-end semiconductor applications.

  - Disadvantages: The equipment is expensive, and the production process is complex.

These methods offer various advantages and disadvantages, making them suitable for different applications and production scales.

Semicorex offers high-purity Silicon Carbide Powder. If you have any inquiries or need additional details, please don't hesitate to get in touch with us.

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