| 主权项 |
1. A non-quenched polycrystalline silicon rod which is easily comminuted, the silicon rod having a rod diameter of >100 mm, and having been prepared by a process comprising depositing polycrystalline silicon by means of chemical vapor deposition from a silicon-containing gas onto a silicon filament rod according to the Siemens method at a deposition temperature, wherein following the deposition, the polycrystalline Si rods are brought into contact with hydrogen during a cooling phase in the reactor, wherein the hydrogen flow rate and/or the hydrogen pressure is/are selected such that the power for maintaining the deposition temperature at the selected hydrogen flow rate and/or pressure is at least 50% of the power required at the end of deposition, but not less than 5 kW per 1 m rod length, and the cooled polycrystalline Si rods have, in perpendicular cross section, cracks and/or radial stresses of at least 1·10−4 cm−1, the cracks and/or radial stresses existing immediately following removal of the polycrystalline silicon rod from the Siemens reactor without any quenching step, wherein 80% of the cross sections in a perpendicular direction with respect to the thin rod have cracks and/or radial stresses larger than 1·10−4 cm−1. |
