| 摘要 |
<p>PROBLEM TO BE SOLVED: To inexpensively and easily produce a high quality polycrystalline silicon low in impurity concentration and high in crystallinity. SOLUTION: The crystalline silicon production apparatus crystallizes, upward from the inner bottom face of a casting mold 2, fused silicon 13 which is stored in the casting mold 2 in a chamber by imparting a positive temperature gradient in the above direction. In the apparatus, a gas supply lance 6 (gas discharge tube) arranged above the casting mold 2 while directing its top toward the inside of the mold 2. The lance 6 is composed of an outer tube 11 and an inner tube 12 provided in such a state as to be inserted into the former. An inert gas (sealing gas) which forms a flow covering the surface of the fused silicon 13 is supplied in a ring-like space S between the outer and inner tubes 11 and 12, and another inert gas (gas for forming a cavity) which makes a flow forming a cavity C on the surface of the fused silicon 13 is supplied in the inner tube 12.</p> |
