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Quartz Crucibles

Quartz Crucibles

-- Steady & Reliable Manufacturer --

High-Volume, High-Purity Quartz Crucibles

Quartz crucibles are specialized, high-capacity vessels fundamental to the production of high-purity polycrystalline silicon (poly-Si) and monocrystalline silicon (mono-Si) ingots for the solar and semiconductor industries. They are designed to withstand the extreme temperatures (up to 1500∘C) and thermal gradients inherent in the Czochralski (Cz) method of crystal growth. Our crucibles are predominantly manufactured using the rotational molding process, which creates a highly uniform wall thickness and a smooth, contamination-free inner surface that is critical for a stable melt and successful crystal pulling. The purity of the quartz, typically in the form of inner clear fused silica layers over an opaque outer layer, is strictly controlled to prevent contamination of the molten silicon, which would drastically reduce the efficiency of the final photovoltaic cell or microelectronic device. We supply a comprehensive range of sizes, from smaller 10-inch R&D units up to massive 32-inch and 36-inch crucibles required for high-volume commercial production. The critical design feature is the transition layer between the clear inner layer (to prevent bubble formation and contamination) and the opaque outer layer (to scatter heat and provide mechanical strength), which must be uniform and defect-free. The overall geometry, including the depth, cone angle, and lip integrity, is meticulously controlled to ensure a perfect fit into the customer's Cz pulling equipment and to maximize the yield of the silicon ingot. We understand that crucible quality is directly tied to crystal yield and pulling speed, making our product a high-value, critical consumable. Beyond the standard Cz process, we also supply crucibles for specialized melt processes and for use as liners in high-temperature induction furnaces for metal alloying, leveraging the non-reactive nature of fused silica. Our quality commitment includes rigorous ultrasonic and visual inspection to detect micro-cracks and air pockets that could lead to failure during the high-stress pulling process. The longevity and reliability of our crucibles translate directly into lower operational costs and higher production efficiency for our clients.

Material and Geometric Specifications

The specifications for quartz crucibles focus on a balance between material purity, thermal performance, and dimensional stability, ensuring they meet the stringent demands of silicon crystal growth.

Parameter Standard Solar Grade High-End Semiconductor Grade Tolerance/Remark
Manufacturing Method Rotational Molding Rotational Molding Ensures uniform wall thickness.
Outer Diameter (OD) 20 to 32 inch 32 to 36 inch (Custom up to 40inch) Sized for specific Cz pullers.
Purity (SiO2​) ≥99.99% ≥99.995% Trace elements Na,K,Fe strictly controlled.
Wall Thickness Uniformity ±1.5mm ±1.0mm Crucial for thermal stability.
Inner Surface Finish Clear Fused Silica Layer Ultra-smooth Clear Silica Reduces bubble formation and contamination.
Devitrification Resistance High (Additive Doping) Highest (Special Doping/Coating) Extends lifespan during the pull.
Base Flatness ≤1mm deviation ≤0.5mm deviation Ensures stable seating in the puller.
Operational Lifetime Single Use (Standard) Single Use (Critical Purity) Used until the pull process is complete.

Our crucibles feature a unique dual-layer construction: the inner clear layer is transparent, preventing the scattering of heat and thus allowing precise control over the silicon melt's temperature profile, while the outer opaque layer contains micro-bubbles that help scatter heat and provide the necessary mechanical strength at high temperatures. Dimensional control is critical: the wall thickness uniformity directly affects the thermal gradient in the melt, impacting the crystal growth rate and crystal defect density. We use non-contact laser measurement systems to confirm the critical dimensions and geometry before shipping. Special attention is paid to the lip, which must remain smooth and clean to prevent issues with the crystal necking process. For certain advanced processes, we can apply proprietary doping or coating to the inner surface to further suppress the formation of SiO gas bubbles, which can cause defects in the growing silicon ingot. Buyers must specify their puller model and silicon melt weight to ensure the correctly sized and structurally reinforced crucible is supplied.

Core Applications in Crystal Growth and Metallurgy

Quartz crucibles are at the heart of the world's most demanding high-purity material processes, dominated by the electronics and energy sectors.

  • Czochralski (Cz) Silicon Crystal Growth:
    • Monocrystalline Silicon (Mono-Si): Used to hold the molten high-ppurity silicon from which a single crystal ingot is pulled. This is the source material for microprocessors and high-efficiency solar cells. The crucible is consumed in a single pull.
  • Polycrystalline Silicon (Poly-Si) Production:
    • Used in certain melting and casting processes where high purity is required before the material is cut into wafers.
  • Advanced Metallurgy and Alloying:
    • Used as a liner or vessel in vacuum or controlled atmosphere induction furnaces for melting and refining high-purity, reactive metals (e.g., titanium, zirconium, or specialized alloys) where contact with ceramic or graphite would introduce unacceptable contamination.
  • Laboratory and Research Furnaces:
    • Used in high-temperature, small-scale melting and synthesis experiments where extreme chemical inertness and resistance to thermal shock are required, often involving precious metals or specialized compounds.

The choice between opaque and clear quartz components within the crucible assembly (e.g., the crucible itself vs. the shield rings) is crucial for controlling the radiation field and heat flow within the furnace. Our team offers consultation to optimize the crucible design and composition for specific crystal growth parameters (pull rate, rotation rate, melt size), ensuring the highest possible quality and yield of the silicon ingot. The sheer size and structural requirement of large-diameter crucibles demand specialized manufacturing facilities, placing our company among a select group of global suppliers capable of meeting this demand.

Advantages for Crystal Growers and Metallurgists

Our advantage in the quartz crucible market stems from a combination of scale, material purity control, and engineering precision for high-yield applications.

  • Superior Inner Surface Purity: The specialized clear fused silica inner layer minimizes the introduction of impurities (especially B and P, which act as dopants) into the molten silicon, directly boosting the electrical performance and efficiency of the resulting solar cells and integrated circuits.
  • Optimized Thermal Performance: Our dual-layer construction (clear inner, opaque outer) is engineered to manage radiant heat transfer efficiently. The opaque outer layer scatters heat, providing insulation and protecting the surrounding components, while the inner clear layer allows for precise thermal control of the melt.
  • High Structural Integrity and Lifespan: Through precise rotational molding and advanced annealing, the crucibles exhibit minimal stress and maximal resistance to creep and collapse at high Cz process temperatures, guaranteeing the vessel maintains its critical shape throughout the entire, expensive pulling process.
  • Minimal SiO Bubble Formation: The ultra-smooth inner surface and controlled raw material purity significantly suppress the evolution of SiO gas bubbles, which is a major source of defects and SiO2​ precipitates in the silicon ingot.
  • Large-Scale Manufacturing Capability: We can consistently supply large-diameter crucibles (32inch,36inch,40inch) with short lead times, essential for high-volume manufacturing facilities that operate continuously.
  • Custom Geometry Matching: Our engineering team works to match the crucible's geometry (cone angle, wall thickness, lip profile) precisely to the customer's specific Cz puller model, ensuring stable rotation, proper heat management, and maximizing the silicon filling ratio.
  • Integrated Supply Chain: Our comprehensive supply chain management for high-purity quartz sands ensures a consistent and uninterrupted flow of raw materials, protecting our clients from supply volatility and unexpected material changes.

We position ourselves as a strategic partner, not just a supplier. Our product quality is an investment in the client's crystal growth yield and efficiency.

Purchasing, Payment Terms, and Global Delivery

Due to the high-value, critical nature and large physical size of quartz crucibles, our trade terms are structured for robust logistics and secure transactions.

  • Payment Conditions: We typically require a 30% to 50% deposit upon order confirmation, with the balance due prior to shipment (Against Bill of Lading copy). We accept T/T Wire Transfer and can discuss irrevocable L/C at Sight for significant volume contracts. We can accommodate multi-year contracts with pre-agreed pricing stability mechanisms.
  • Specialized Packaging: Each quartz crucible, especially the large-diameter units, is packaged in a single, custom-built, heavy-duty wooden crate. The crate is reinforced and includes internal suspension or foam padding to prevent any contact or micro-fracture during sea or air transport. All packaging is suitable for stacking and long-term storage.
  • Logistics and INCOTERMS: Given the size, sea freight under CIF (Cost, Insurance, and Freight) or CFR (Cost and Freight) is common for bulk orders, while urgent or small sample orders can be shipped via specialized air cargo. We manage all export customs clearance and provide comprehensive marine or air cargo insurance to cover the full value of the shipment. We use specialized, reliable freight forwarders experienced in handling fragile, high-value industrial goods.
  • Lead Time Calculation: Large-diameter, custom-molded crucibles have a lead time of 4 to 8 weeks, depending on the size and current production queue. Repeat orders for standard sizes can often be expedited to 3-4 weeks. The manufacturing cycle is long due to the rotational molding, annealing, and meticulous quality control steps.
  • Warranty and Damage Claims: We guarantee the crucible meets all specified dimensional and purity requirements. In the event of transit damage, clients must document the damage immediately upon receipt, and we will handle the insurance claim and dispatch replacement units as quickly as possible, minimizing production disruption. We also offer on-site consultation for large contracts to ensure proper handling procedures are in place.

Essential Frequently Asked Questions on Crucibles

  • Q: Why is the clear inner layer necessary in a quartz crucible?

    A: The clear inner layer, made from high-purity fused silica, is critical for two reasons. First, its ultra-smooth, high-purity surface is less likely to react with molten silicon or release impurities. Second, and most importantly, the clear layer is highly resistant to the SiO gas bubble formation that occurs when molten silicon attacks the quartz at high temperatures. These bubbles, if they escape, can cause crystal defects. By having a clear layer, bubble formation is suppressed at the critical interface with the melt, leading to higher quality, defect-free silicon ingots.

  • Q: What causes devitrification, and how does your crucible resist it?

    A: Devitrification is the process where amorphous (glassy) quartz converts into a crystalline form (Cristobalite) when exposed to high temperatures, especially in the presence of Na or K contamination. The crystalline layer is weaker and can easily flake off, contaminating the silicon melt and often causing the crucible to crack. Our crucibles resist devitrification through a combination of ultra-high purity materials (reducing alkali metal catalysts) and proprietary additives or coatings on the outer opaque layer. The opaque layer itself is designed to handle this phase change without immediate catastrophic failure, extending the usable life for the single pull required in the Cz process.

  • Q: Can quartz crucibles be reused after a single silicon pull?

    A: No, standard quartz crucibles used in the Cz method are considered single-use consumables. During the crystal pulling process, the molten silicon reacts with the inner quartz surface, forming a layer of SiO2​ and SiO gas. The structural integrity is compromised, and the inner surface is partially consumed and contaminated. Attempting to reuse the crucible would severely risk crystal defects, high contamination, and mechanical failure during the next pull. For this high-purity, high-value process, a new crucible is mandated for every silicon ingot pull to ensure yield and quality.

  • Q: How should I handle and store the large quartz crucibles before use?

    A: Proper handling and storage are crucial to prevent micro-cracks and contamination. Crucibles should always be kept in their original sealed packaging in a dry, clean environment until immediately prior to use. They should only be handled using cleanroom gloves or specialized vacuum lift systems to avoid contact with human skin oils or atmospheric dust, which can introduce contaminants. Any visible damage or contamination on the inner surface can compromise the silicon melt, so extreme care and cleanroom protocols must be maintained at all times when handling this critical component.

From Made-in-China to
Global Smart Manufacturing

Yancheng Mingyang Quartz Products Co., Ltd. is a company specializing in the production of quartz and special glass products. Yancheng Mingyang Quartz Products Co., Ltd. is the production plant of Jinzhou Mingde Quartz Glass Co., Ltd. in Jiangsu, Since its establishment, the company has developed rapidly, introduced advanced technology and production equipment at home and abroad, and continuously improved and improved product quality. Relying on its own advantages, we have developed a variety of products suitable for the market and meet the needs of different customers, and solved many urgent production problems for our customers.

The company's products include quartz glass tubes, double-hole quartz glass tubes, quartz glass rods, quartz sheets, sapphire windows, calcium fluoride glass windows, infrared ultraviolet coatings, high-pressure resistant aluminosilicate glass window panels, quartz glass instruments, high borosilicate glass instruments, quartz crucibles, quartz gold-plated tubes, quartz heaters, quartz infrared heating tubes, far-infrared directional radiation heaters ultraviolet germicidal lamps and other special types of quartz glass products.

Yancheng Mingyang Quartz Products Co., Ltd.
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