Joe L Walker

US Patent:

45377596, Aug 27, 1985

Filed:

Jun 27, 1983

Appl. No.:

6/507768

Inventors:

Joe M. Walker - Pittsburg KS
Thomas M. Potts - Miami OK

Assignee:

Eagle-Picher Industries, Inc. - Cincinnati OH

International Classification:

C01B 3302

US Classification:

423349

Abstract:

Elemental silicon is produced by a process and apparatus wherein relatively impure silane (SiH. sub. 4) is purified in the gaseous state, while mixed with an inert carrier gas, to a content of electronically active impurities which is no higher than that of "electronic grade" silicon. The silane so purified is then thermally decomposed to form elemental silicon of electronic grade purity, without need for further purification of the elemental silicon itself. The silane purification is carried out by injecting the impure silane gas as a series of timed, spaced pulses into a carrier gas stream which transports the silane pulses to a gas chromatographic column, through which the pulses flow in sequence. The column has a porous polymer or a molecular sieve packing which is specially preconditioned to achieve high resolution separation of the components of the feed. The components of each pulse are differentially retarded by this packing so that they move through the column at different rates, as a result of which they exit at different but precisely spaced time intervals in relation to pulse input time.