| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a polycrystalline silicon rod which is resistant to breakage and of high quality by screening a hard polycrystalline silicon rod in a simple manner. <P>SOLUTION: The length of a polycrystalline silicon rod (100) is measured with a measuring tape followed by striking the polycrystalline silicon rod (100) with a hammer (120), and a striking sound is recorded on a recorder (140) via a microphone (130). The sound signal of the striking sound is subjected to fast Fourier transformation and frequency distribution is displayed. In the frequency distribution after fast Fourier transformation, a peak frequency f which indicates the highest sound volume is detected. The relationship between the length of the polycrystalline silicon rod (L) and the peak frequency f is found out to determine the hardness of the polycrystalline silicon rod according to whether or not the peak frequency f belongs to the region of f≥1471/L (A region). <P>COPYRIGHT: (C)2012,JPO&INPIT |
