摘要 |
<p>Semiconductor grade polysilicon in the form of free flowing, approximately spherical particles produced in a fluidized bed, and having a reduced surface silicon dust content and hydrogen content. Such products are formed in two operations utilizing fluidized beds. In the first operation, silicon is deposited on polysilicon seed particles. In the second operation, trichlorosilane or other halogenated silane is decomposed at an elevated temperature to provide a thin silicon coat, which binds the silicon fines to the larger particles. While the particles are exposed to the decomposition temperature employed, hydrogen diffuses out of the particles resulting in a reduction in hydrogen content and producing a polysilicon particle with a smooth shiny surface.</p> |