For the Purpose of preparing high purity state of silicon, the hydrogen reduction of trichlorosilane by the open tube flow process was used. The trichlorosilane available for the raw material in large quantities for the silicon industry was distilled for the starting material. The distilled trichlorosilane was vaporized by bubbling at 0℃ with small quantity of hydrogen. The hydrogen reduction of trichlorosilane was carried out in a quartz tube. The resultant yield was compared with the theoretical one calculated thermodynamically. The optimum condition was obtained at 1100℃ and 60-100 mole ratio of hydrogen to trichlorosilane. Its yield was 60-70%. The deposited silicon showed a polycrystalline dense mass of lustrous appearance. It was treated with hydrofluoric acid to clean the surface. The purity of product silicon analyzed by the emission spectroscopy was higher than 99.999%.
