Purification of Silicon by the Silicon Fluoride Transport Process. Thermochemical Study

摘要

A computer-assisted thermochemical equilibrium analysis was conducted for the silicon transport reaction: Si(s) + SiF sub 4 (g) = (intermediates) = Si(s) + SiF sub 4 (g). The calculations indicated that a substantial transport rate should be possible at temperatures of 1700 exp 0 K and one atmosphere pressure. Computations were made to determine whether the elemental impurities present in metallurgical-grade silicon would transfer in this process. It was concluded that aluminum, chromium, copper, iron, manganese, molybdenum, nickel, vanadium, and zirconium would not transfer, but that boron, magnesium, phosphorus, and titanium would transfer. (ERA citation 05:015141)