| abstract |
A chunk polycrystalline silicon having a carbon concentration on the surface of 0.5-35 ppbw is provided. A heat treatment of a polycrystalline silicon chunk in a reactor at a temperature of 350 to 600 ° C., wherein the polycrystalline silicon chunk is present in an inert gas atmosphere during the heat treatment, and the polycrystalline silicon chunk after the heat treatment. Cleaning a polycrystalline silicon chunk having carbon contamination on the surface, having a surface carbon concentration of 0.5-35 ppbw. [Selection figure] None |