| 摘要 |
A set of three low cost processes for removing boron, phosphorus, carbon and other metal and nonmetal impurities during the process of converting metallurgical grade silicon to electronic grade silicon. One process removes boron by using one or more high temperature solids removal devices to remove solid titanium diboride from a halosilane reactor effluent stream where the high temperature is preferably greater than 200 C, more preferably greater than 300 C and most preferably greater than 400 C. A second process removes carbon as methane and phosphorus as phosphine by means of a membrane separator which processes all or part of a hydrogen recycle stream to recover hydrogen while rejecting methane and phosphine. A third process separates a high boiling halosilane stream into a large low impurity stream and one or more small high impurity streams some of which can be sent for halogen recovery. |
