Solar Grade Silicon production through trichlorosilane decomposition

The traditional polysilicon processes are evolving to address the low energy consumption requirement for the production of solar grade silicon. This aim requires understanding of the fluid dynamic phenomena that takes place during the polysilicon deposition in the traditional Siemens reactor. The model for polysilicon deposition briefly presented in this paper analyzes the dependence of the growth rate, deposition efficiency, and power-loss on the gas velocity, the mixture of gas composition (trichlorosilane and hydrogen), the reactor pressure, the gas inlet temperature, and the rod surface temperature. A laboratory scale polysilicon reactor has been constructed in order to validate the information obtained through the aforementioned model on the different deposition features. The system consists of a quartz reactor vessel where a silicon rod is heated by Joule effect, a TCS and H₂ gas mixture supplier, and a recirculation system that diminishes the gas wasting.