Quartz devices in solar cell manufacturing

In the production line of solar cells, there is a type of seemingly inconspicuous but crucial component - high-purity quartz products. They are not directly involved in photoelectric conversion, but like loyal guards, they ensure that each silicon wafer "grows" safely in high temperature, corrosive gases and complex processes. It is these transparent quartz devices that support the efficient operation of the modern photovoltaic industry.

Ⅰ. Quartz: the “golden supporting role” in solar energy manufacturing

The core material of solar cells is silicon, and the processing of silicon is inseparable from high temperature and chemical treatment. Ordinary materials can hardly withstand such extreme environments, but quartz (mainly composed of silicon dioxide) can do it perfectly because of its three major characteristics:

A) High temperature resistance: The melting point of quartz is as high as over 1700℃, while the diffusion and annealing processes of solar cells are usually carried out at 800-1200℃. Quartz devices remain stable at high temperatures.

B) High purity: The purity of solar-grade quartz is over 99.99%, which prevents impurities from contaminating silicon wafers and affecting battery efficiency.

C) Chemical inertness: Quartz hardly reacts with acids, alkalis and most gases, and can be used for a long time even in highly corrosive process gases (such as chlorine and hydrogen fluoride).

These properties make quartz an irreplaceable material in solar cell manufacturing. From the support of silicon wafers to the delivery of process gases, quartz devices run through the entire production process.

Ⅱ. Quartz "Team" on the Solar Cell Production Line

In photovoltaic factories, quartz products have different forms and functions to ensure the precise execution of each process. The following are several key quartz products for solar cells:

1. Mother Boat Carrier

Function: The "transporter" of silicon wafers, carrying a large number of silicon wafers during cleaning, diffusion and other processes.

Features: Precision-designed grooves ensure consistent spacing between silicon wafers to avoid adhesion at high temperatures.

2. Quartz Boat

Function: Used in diffusion furnaces, PECVD (plasma enhanced chemical vapor deposition) and other equipment to carry silicon wafers for high-temperature processing.

Evolution: Early quartz boats were simple flat-plate designs, but now have developed optimized structures such as wavy shapes and baffles to improve gas flow uniformity.

3. Long Boat

Adaptation trend: As the size of silicon wafers increases (such as 182mm and 210mm large silicon wafers), the length of the long boat also increases to ensure that the silicon wafers are evenly heated in the high-temperature furnace.

4. Quartz Bottle

Function: Storage and transportation of high-purity liquid or gaseous chemicals, such as silicon source gas (SiH₄), dopant (POCl₃), etc.

Key requirements: Ultra-high sealing to prevent gas leakage or external contamination.

5. Quartz Furnace Tube

Core components: The "heart" of the diffusion furnace and annealing furnace, where silicon wafers undergo high-temperature doping or annealing.

Challenge: Under long-term high temperatures, quartz furnace tubes may undergo devitrification, resulting in a decrease in strength, so special treatment is required to extend life.

6. Tube Welding

Process difficulties: Quartz welding requires hydrogen-oxygen flame or laser welding technology to ensure that the weld is free of bubbles and cracks, otherwise it may break during high and low temperature cycles.

7. Quartz Sheaths

Protective function: Wrap the thermocouple or sensor to enable it to work stably for a long time in a corrosive gas environment.

8. Door Cap

Sealing and insulation: prevent heat loss and isolate outside air from entering the high-temperature reaction area.

Ⅲ. Challenges and Future of Quartz Devices

Although quartz occupies an important position in photovoltaic manufacturing, it also faces some challenges:

● Lifespan issues: Under long-term high temperatures, quartz will gradually crystallize, resulting in a decrease in strength, and usually needs to be replaced after 300-500 uses.

● Cost pressure: High-purity quartz sand resources are limited, and prices have fluctuated greatly in recent years, prompting the industry to develop quartz products or alternatives with longer lifespans.

● Large size adaptation: As the size of silicon wafers increases, quartz boats, furnace tubes and other devices also need to be upgraded accordingly, which puts higher requirements on the manufacturing process.

In the future, quartz devices may develop in the direction of composite (such as quartz-silicon carbide composite materials) and intelligent (integrated sensors to monitor status in real time) to better meet the manufacturing needs of high-efficiency solar cells.

Ⅳ. Conclusion

Although quartz devices are not directly involved in power generation, they are the "behind-the-scenes heroes" of solar cell manufacturing. From the quartz boats that carry silicon wafers to the quartz furnace tubes that protect the process, they ensure the efficient and stable production of each solar cell. With the advancement of photovoltaic technology, quartz products are also constantly evolving, continuing to safeguard the future of clean energy.