The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 24, 1978
Filed:
Jul. 21, 1976
William Martell Ingle, Phoenix, AZ (US);
Motorola Inc., Schaumberg, IL (US);
Abstract
Truly amorphous silicon having a low level of undesired impurities, and therefore suitable for semiconductor applications, may be prepared by the present process. Impure silicon, for example, metallurgical grade silicon, is prepared at an elevated temperature, e.g., above 1400.degree. C. The impure silicon and at least one binary silicon fluoride compound, e.g., silicon tetrafluoride, are chemically combined at the elevated temperature to form silicon difluoride gas. The silicon difluoride gas is polymerized. The silicon difluoride polymer is then thermally decomposed to produce the purified, amorphous silicon and binary silicon fluoride by-products. The binary silicon fluorides are recycled in the process to be chemically combined with the impure silicon. That step and the succeeding steps serve to reduce the level of unwanted impurities in the silicon produced by at least several orders of magnitude.