| 摘要 |
A silicon halide or silicon hydride halide, e.g. silicon tetrachloride or silico-chloroform, which is liquid at normal room temperature and is to be used for producing ultra-pure silicon for semiconductors, is purified from 'n-doping' impurities, i.e. compounds containing an element of Group V of the Periodic system, by adding to the liquid at least one boron halide. This forms addition compounds with any 'n-doping' impurity, present, e.g. a phosphorus containing compound, and these addition compounds remain in the residue when the liquid silicon compound is evaporated, e.g. at a temperature, in the range 18 DEG C. to 30 DEG C. and the vapours so produced are substantially free from 'n-doping' impurities. The quantity of boronhalide added may be such that, for example, in the case of phosphorus the atomic ratio of boron to phosphorus is less than 100 and is preferably approximately 1. The purified vapours can be reduced to pure silicon in a reaction vessel in which the silicon is deposited on electrically heated carrier rods as disclosed in Specification 861,135. |
