Polysilicon

In polysilicon the usual priorities invert: throughput is easy, purity is everything.

Contact material decides the value

Iron, chromium and nickel picked up from a chute wall travel into the ingot and reduce cell efficiency.

• Polymer, quartz or ceramic liners on every contact surface.
• No bare steel fasteners, edges or inspection covers in the product path.
• Documented liner wear checks, since a worn liner exposes the steel beneath.

Breakage and fines

Silicon is hard and brittle, so impacts produce sharp fines with a very high surface area.

Those fines both carry contamination and are combustible, which makes the reclamation system a safety item as well as a yield item.

Powder reclamation

Fines generated in crushing and handling have real value if they are collected cleanly.

Closed vacuum conveying into dedicated containers keeps the reclaimed powder within specification rather than mixing it with plant dust.

Cleanroom discipline

Packing is usually done in a controlled environment with gloves, liners and sealed bags, and the handling equipment has to fit that regime rather than fight it.

What to establish before buying equipment

• Purity specification and the acceptable metallic pickup per transfer.
• Liner material and its wear and particle shedding behavior.
• Fines target and the reclamation route.
• Explosion protection for the fines collection system.

Polysilicon is handled for purity above everything else.

Any contact with ordinary metal adds contamination that the downstream process cannot remove, so the storage containers, the gloves and the tools are part of the specification.

• Dedicated, non-metallic or lined contact surfaces throughout.
• Controlled environment: particles from the room become contamination in the product.
• Segregate grades rigorously; mixing them downgrades the better one.

Everything is chosen to avoid adding anything to the material.

Chunks are hard and sharp enough to abrade ordinary equipment, and whatever they abrade ends up in the product. That makes lined or non-metallic surfaces normal and makes gentle handling a purity measure.

• Lined or non-metallic contact surfaces, verified rather than assumed.
• Low drop heights to limit both breakage and abrasion of the equipment.
• Closed transfer to keep room particles out.

Fine silicon powder is combustible and the chunks are a mechanical hazard.

• Explosion protection where fines are generated, such as crushing and sizing.
• Cut protection for anyone handling chunks.
• Respiratory protection where fines are produced; the respirable fraction matters.