Quality analysis of polycrystalline silicon produced by modified Siemens process

Polycrystalline silicon with good quality was produced using silicon metal as raw material by modified Siemens process. The impurity contents of the purified trichlorosilane, the P, B, C, O contents of polycrystalline silicon and the resistivity of P, B were analyzed by ICP-MS, low-temperature Fourier transform infrared spectroscopy, polycrystalline silicon atmosphere zone melting base-phosphorus and silicon-polycrystalline vacuum zone melting base-boron testing method, respectively. The testing results of product quality of polycrystalline silicon produced by modified Siemens process were reported, which show that the obtained polycrystalline silicon is of high quality. Various factors influencing the product quality of polycrystalline silicon have been discussed, including the changing curves of the temperature, feeding speed about the gas mixtures and the electrical voltage and current of AEG during the whole growing process in the reduction furnace. The quality of the intermediates, such as purified trichlorosilane and hydrogen, used for producing polycrystalline silicon was also analyzed. The results have laid a reliable foundation for steadily producing high-quality polycrystalline silicon.