CHUNK POLYCRYSTALLINE SILICON AND PROCESS FOR CLEANING POLYCRYSTALLINE SILICON CHUNKS

摘要

The invention provides chunk polycrystalline silicon having a concentration of carbon at the surface of 0.5-35 ppbw. A process for cleaning polycrystalline silicon chunks having carbon contaminations at the surface, comprising a thermal treatment of the polycrystalline silicon chunks in a reactor at a temperature of 350 to 600°, the polycrystalline silicon chunks being present in an inert gas atmosphere during the thermal treatment, and the polycrystalline silicon chunks after the thermal treatment having a concentration of carbon at the surface of 0.5-35 ppbw.