Purification of silicon source materials
AssigneeMotorola, Inc.
InventorsRobert D. Darnell, William M. Ingle
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Abstract
A process is disclosed for the purification of trichlorosilane and other silicon source materials. Trace impurities of boron and phosphorous are removed from trichlorosilane by reacting small amounts of oxygen with the trichlorosilane at a temperature between about 170.degree. and 300.degree. C. The oxygen reacts with the Si--H bond in HSiCl.sub.3 to form a "SiOH" species which in turn complexes impurities such as BCl.sub.3 or PCl.sub.3 present in the trichlorosilane. Purification of the trichlorosilane is then easily accomplished during a subsequent distillation step which separates the purified trichlorosilane from the less volatile complexed boron or phosphorous compounds.
Claims4
A process for removing BCl.sub.3 and/or PCl.sub.3 impurities from a silicon source material including trichlorosilane which comprises the steps of:
- heating said material in gaseous form to a temperature of about 170.degree. C. to about 300.degree. C. with oxygen to effect formation of boron and/or phosphorous containing siloxane complexes;
- and
- distilling to remove said siloxane complexes from said source material.
Dependencies are inferred from the claim text.