摘要 |
Cubic polycrystalline silicon chunks comprise less than 200 parts per trillion by weight (pptw) of metal and less than 50 parts per trillion atoms (ppta) of dopant on their surfaces. An independent claim is included for producing polycrystalline silicon chunks comprising comminuting a polycrystalline silicon rod into cubic chunks, and cleaning the polycrystalline silicon chunks, where the comminuting step takes place using a spiked-roll crusher having at least one spiked roll, which comprises tungsten carbide phases and 0.1-10% of a metal carbide consisting of titanium carbide, chromium carbide, molybdenum carbide, vanadium carbide and nickel carbide. |